diff --git a/package-lock.json b/package-lock.json
index f3034c0..91b8c65 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -16,6 +16,7 @@
         "react-dom": "^19.2.7",
         "vega": "^6.2.0",
         "vega-embed": "^7.1.0",
+        "vega-expression": "^6.1.0",
         "vega-lite": "^6.4.2",
         "vega-themes": "3.0.0",
         "zustand": "^5.0.14"
diff --git a/package.json b/package.json
index 9cc7b0a..a8a67a1 100644
--- a/package.json
+++ b/package.json
@@ -32,6 +32,7 @@
     "react-dom": "^19.2.7",
     "vega": "^6.2.0",
     "vega-embed": "^7.1.0",
+    "vega-expression": "^6.1.0",
     "vega-lite": "^6.4.2",
     "vega-themes": "3.0.0",
     "zustand": "^5.0.14"
diff --git a/src/app/components/DatasetsModal.tsx b/src/app/components/DatasetsModal.tsx
index dfe4cfd..ee4dc08 100644
--- a/src/app/components/DatasetsModal.tsx
+++ b/src/app/components/DatasetsModal.tsx
@@ -14,9 +14,16 @@
 
 import { useMemo, useState } from 'react';
 import { useShallow } from 'zustand/react/shallow';
-import { datasetReference, tabularRows, type DataSource, type Dataset } from '@core/dataset';
+import {
+  cellText,
+  datasetReference,
+  tabularRows,
+  type DataSource,
+  type Dataset,
+} from '@core/dataset';
 import { detectFormat, detectFormatFromUrl, type DataFormat } from '@core/format-detection';
 import { datasetUsageCounts, snippetsReferencingDataset } from '@core/relationships';
+import { humanizeBytes } from '@core/storage-estimate';
 import { closeModal, openModal, resnapshot } from '../modals/ModalCoordinator';
 import { fetchRemoteData } from '../infrastructure/remote-data';
 import { remoteFetchErrorMessage } from '../services/remote-data-errors';
@@ -38,15 +45,6 @@ function formatLabel(format: DataFormat): string {
   return format === 'topojson' ? 'TopoJSON' : format.toUpperCase();
 }
 
-/** Human-readable byte size (B / KB / MB). */
-function humanBytes(bytes: number): string {
-  if (bytes < 1024) return `${bytes} B`;
-  const kb = bytes / 1024;
-  if (kb < 1024) return `${kb < 10 ? kb.toFixed(1) : Math.round(kb)} KB`;
-  const mb = kb / 1024;
-  return `${mb < 10 ? mb.toFixed(1) : Math.round(mb)} MB`;
-}
-
 const SOURCE_OPTIONS: ReadonlyArray<SegmentedOption<DataSource>> = [
   { value: 'inline', label: 'Inline' },
   { value: 'url', label: 'URL' },
@@ -55,14 +53,6 @@ const SOURCE_OPTIONS: ReadonlyArray<SegmentedOption<DataSource>> = [
 /** Rows shown in the tabular preview before truncating (spec §05 → Detail Panel). */
 const PREVIEW_ROW_LIMIT = 50;
 
-/** One table cell's text: blank for empty, the string as-is, else JSON (numbers,
- *  booleans, nested values). Avoids `String()` on objects ("[object Object]"). */
-function cellText(value: unknown): string {
-  if (value == null) return '';
-  if (typeof value === 'string') return value;
-  return JSON.stringify(value);
-}
-
 export function DatasetsModal() {
   const datasets = useDatasetStore(useShallow((s) => s.datasets));
   const view = useDatasetStore((s) => s.view);
@@ -137,7 +127,7 @@ function DatasetListItem({
   if (unfetched) parts.push('not fetched');
   else if (dataset.rowCount !== null) parts.push(`${dataset.rowCount} rows`);
   parts.push(formatLabel(dataset.format));
-  if (!unfetched) parts.push(humanBytes(dataset.size));
+  if (!unfetched) parts.push(humanizeBytes(dataset.size));
 
   return (
     <li className={`${styles.item} ${active ? styles.itemActive : ''}`}>
@@ -324,7 +314,7 @@ function DatasetDetail({
           </div>
           <div>
             <dt>Size</dt>
-            <dd>{dataset.data == null ? 'N/A' : humanBytes(dataset.size)}</dd>
+            <dd>{dataset.data == null ? 'N/A' : humanizeBytes(dataset.size)}</dd>
           </div>
         </dl>
 
diff --git a/src/app/components/Icon.tsx b/src/app/components/Icon.tsx
index 7bfbeaa..70856d2 100644
--- a/src/app/components/Icon.tsx
+++ b/src/app/components/Icon.tsx
@@ -47,7 +47,7 @@ export type IconName =
   | 'status-info'; // Carbon InformationFilled
 
 /** Carbon icon scale (arch 09 §5.3). 16px (sm) is the default, paired to 14px body. */
-export type IconSize = 'sm' | 'md' | 'lg' | 'xl';
+type IconSize = 'sm' | 'md' | 'lg' | 'xl';
 
 /** Inner SVG geometry per glyph, on Carbon's 0 0 32 32 grid. fill comes from CSS. */
 const GLYPHS: Record<IconName, ReactNode> = {
diff --git a/src/app/infrastructure/db.ts b/src/app/infrastructure/db.ts
index 9156afc..6ff4ea6 100644
--- a/src/app/infrastructure/db.ts
+++ b/src/app/infrastructure/db.ts
@@ -99,9 +99,6 @@ function tx<T>(
   );
 }
 
-export const get = <T>(store: string, key: IDBValidKey): Promise<T | undefined> =>
-  tx<T | undefined>(store, 'readonly', (s) => s.get(key) as IDBRequest<T | undefined>);
-
 export const getAll = <T>(store: string): Promise<T[]> =>
   tx<T[]>(store, 'readonly', (s) => s.getAll() as IDBRequest<T[]>);
 
diff --git a/src/app/infrastructure/url-hash.ts b/src/app/infrastructure/url-hash.ts
index 742679a..d9f01cb 100644
--- a/src/app/infrastructure/url-hash.ts
+++ b/src/app/infrastructure/url-hash.ts
@@ -87,6 +87,11 @@ export function readView(): ViewState {
   return parseHash(window.location.hash);
 }
 
+/** The current raw hash, for comparing a serialized view against the URL. */
+export function currentHash(): string {
+  return window.location.hash;
+}
+
 /**
  * Build the next URL for `view`. The hash is the app's only view-state channel,
  * so we normalize to a hash-only canonical URL: any stray query string (a shared
diff --git a/src/app/modals/ModalCoordinator.ts b/src/app/modals/ModalCoordinator.ts
index a61e8a8..4a6c09e 100644
--- a/src/app/modals/ModalCoordinator.ts
+++ b/src/app/modals/ModalCoordinator.ts
@@ -48,7 +48,7 @@ export function resnapshot(): void {
 }
 
 /** True when the active modal's editable state differs from its baseline. */
-export function hasUnsavedChanges(): boolean {
+function hasUnsavedChanges(): boolean {
   const name = useAppStore.getState().activeModal;
   if (!name) return false;
   const current = snapshotOf(name);
diff --git a/src/app/modals/UrlStateSync.ts b/src/app/modals/UrlStateSync.ts
index fb61d5e..f6b8536 100644
--- a/src/app/modals/UrlStateSync.ts
+++ b/src/app/modals/UrlStateSync.ts
@@ -34,6 +34,7 @@ import { useChartBuilderStore } from '../stores/ChartBuilderStore';
 import { useDatasetStore } from '../stores/DatasetStore';
 import { useSnippetStore } from '../stores/SnippetStore';
 import {
+  currentHash,
   pushView,
   readView,
   replaceView,
@@ -72,7 +73,7 @@ export function deriveViewState(): ViewState {
 
 /** True when `view` already matches the current URL hash. */
 function isCurrent(view: ViewState): boolean {
-  return serializeHash(view) === window.location.hash;
+  return serializeHash(view) === currentHash();
 }
 
 /**
@@ -174,12 +175,6 @@ export function startRouting(): void {
   useChartBuilderStore.subscribe(syncUrlFromState);
 }
 
-/** Test seam: reset the module's start/applying flags between cases. */
-export function resetRoutingForTest(): void {
-  started = false;
-  applying = false;
-}
-
 // --- Coordinator seam (unchanged call sites) -------------------------------
 // The coordinator calls these on modal open/close; both now just re-derive the
 // hash from state. Kept as named exports so ModalCoordinator needs no edit.
diff --git a/src/app/orchestration/panes.ts b/src/app/orchestration/panes.ts
index dfdaefc..b0d35fd 100644
--- a/src/app/orchestration/panes.ts
+++ b/src/app/orchestration/panes.ts
@@ -17,7 +17,7 @@ import {
 import { usePanesStore } from '../stores/PanesStore';
 
 /** Delay before a settled resize is persisted. */
-export const PANES_PERSIST_DEBOUNCE_MS = 300;
+const PANES_PERSIST_DEBOUNCE_MS = 300;
 
 /** Hydrate persisted pane widths + visibility into the store. Call before render. */
 export function initPanes(): void {
diff --git a/src/app/services/chart-renderer.ts b/src/app/services/chart-renderer.ts
index dfd9abe..faea204 100644
--- a/src/app/services/chart-renderer.ts
+++ b/src/app/services/chart-renderer.ts
@@ -12,7 +12,7 @@ import type { VisualizationSpec } from 'vega-embed';
 import type { Config } from 'vega-lite';
 
 /** Options for `RenderHandle.toImageURL` (spec §08 → Per-chart export). */
-export interface ImageExportOptions {
+interface ImageExportOptions {
   /**
    * Pixel-density multiplier for the **PNG** raster, **relative to the device**.
    * The image is drawn at `scale × devicePixelRatio` logical-pixel density, so
@@ -80,7 +80,7 @@ export interface RenderOptions {
  * size against this (÷ dpr, since the backing store is dpr× the CSS size) and
  * throws `ChartTooLargeError` rather than handing back a blank canvas.
  */
-export const MAX_CANVAS_PX = 32767;
+const MAX_CANVAS_PX = 32767;
 
 /**
  * Thrown by `renderSpec` when a **canvas**-backed chart resolves to a height larger
diff --git a/src/app/services/spec-config-actions.ts b/src/app/services/spec-config-actions.ts
index 4146f3c..aac4a96 100644
--- a/src/app/services/spec-config-actions.ts
+++ b/src/app/services/spec-config-actions.ts
@@ -110,12 +110,20 @@ export function runMergeChartTheme(editor: monaco.editor.IStandaloneCodeEditor):
   });
 }
 
-/** Remove the draft's `config` block, copying it to the clipboard first. */
-export async function runExtractConfig(editor: monaco.editor.IStandaloneCodeEditor): Promise<void> {
+/**
+ * Shared prologue of the two extract actions: the model, the spec parsed off it,
+ * and the config split out — or null (after toasting) when any step has nothing
+ * to work with.
+ */
+function extractableConfig(editor: monaco.editor.IStandaloneCodeEditor): {
+  model: monaco.editor.ITextModel;
+  rest: Record<string, unknown>;
+  config: Record<string, unknown>;
+} | null {
   const model = editor.getModel();
-  if (!model) return;
+  if (!model) return null;
   const spec = parseSpecObject(model);
-  if (!spec) return;
+  if (!spec) return null;
 
   const { spec: rest, config } = extractConfigFromSpec(spec);
   if (config === null) {
@@ -124,8 +132,16 @@ export async function runExtractConfig(editor: monaco.editor.IStandaloneCodeEdit
       title: 'No config to extract',
       message: 'This spec has no config block.',
     });
-    return;
+    return null;
   }
+  return { model, rest, config };
+}
+
+/** Remove the draft's `config` block, copying it to the clipboard first. */
+export async function runExtractConfig(editor: monaco.editor.IStandaloneCodeEditor): Promise<void> {
+  const extracted = extractableConfig(editor);
+  if (!extracted) return;
+  const { model, rest, config } = extracted;
 
   // Copy before removing — if the clipboard write fails, the spec keeps its
   // config and nothing is lost.
@@ -157,20 +173,9 @@ export async function runExtractConfig(editor: monaco.editor.IStandaloneCodeEdit
  * non-overlapping keys stop applying once the new theme replaces it.)
  */
 export function runExtractConfigToTheme(editor: monaco.editor.IStandaloneCodeEditor): void {
-  const model = editor.getModel();
-  if (!model) return;
-  const spec = parseSpecObject(model);
-  if (!spec) return;
-
-  const { spec: rest, config } = extractConfigFromSpec(spec);
-  if (config === null) {
-    notify({
-      kind: 'info',
-      title: 'No config to extract',
-      message: 'This spec has no config block.',
-    });
-    return;
-  }
+  const extracted = extractableConfig(editor);
+  if (!extracted) return;
+  const { model, rest, config } = extracted;
 
   const snippet = selectActiveSnippet(useSnippetStore.getState());
   const theme = useCustomThemeStore
diff --git a/src/app/services/transfer.ts b/src/app/services/transfer.ts
index d2b09b7..62aea29 100644
--- a/src/app/services/transfer.ts
+++ b/src/app/services/transfer.ts
@@ -27,6 +27,7 @@ import {
   reassignCollidingSnippetIds,
 } from '@core/import-normalize';
 import { snippetSizeBytes } from '@core/snippet';
+import { humanizeBytes } from '@core/storage-estimate';
 import { downloadJson, readTextFile } from '../infrastructure/file-transfer';
 import { deleteSnippet, saveSnippet, StorageQuotaError } from '../infrastructure/snippet-store';
 import { notify } from '../stores/NotificationStore';
@@ -36,13 +37,6 @@ import { useSnippetStore } from '../stores/SnippetStore';
 /** Practical snippet-storage budget (spec §02 storage monitor / §08). */
 const SNIPPET_BUDGET_BYTES = 5 * 1024 * 1024;
 
-/** Round bytes to a short KB/MB string for the overage warning. */
-function formatBytes(bytes: number): string {
-  const kb = bytes / 1024;
-  if (kb < 1024) return `${Math.max(1, Math.round(kb))} KB`;
-  return `${Math.round(kb / 1024)} MB`;
-}
-
 /**
  * Export the whole workspace to a downloaded JSON file (spec §08 → Export).
  * Flushes the live editor buffer first so in-progress draft edits are included.
@@ -209,7 +203,7 @@ export async function importWorkspace(file: File): Promise<void> {
   }
   if (overage > 0) {
     clauses.push(
-      `This puts snippet storage about ${formatBytes(overage)} over the ~5 MB budget; ` +
+      `This puts snippet storage about ${humanizeBytes(overage)} over the ~5 MB budget; ` +
         `consider deleting some snippets.`,
     );
   }
diff --git a/src/app/stores/AppStore.ts b/src/app/stores/AppStore.ts
index 899bea0..45f88c1 100644
--- a/src/app/stores/AppStore.ts
+++ b/src/app/stores/AppStore.ts
@@ -14,11 +14,6 @@ import type { ModalName } from '../modals/types';
  * docs/architecture/01-state-and-stores.md.
  */
 
-export type { UiTheme };
-// The modal union is defined once in the modal system (docs/architecture/03) and
-// re-exported here for the many callers that reach it through the app store.
-export type { ModalName };
-
 export interface AppState {
   /** Active UI theme; mirrored onto <html data-theme> by a subscriber. */
   uiTheme: UiTheme;
diff --git a/src/app/stores/CustomThemeStore.ts b/src/app/stores/CustomThemeStore.ts
index ca04008..19a748e 100644
--- a/src/app/stores/CustomThemeStore.ts
+++ b/src/app/stores/CustomThemeStore.ts
@@ -25,7 +25,7 @@ import { customThemeSelection } from '@core/vega-themes';
 import { useAppStore } from './AppStore';
 
 /** The Theme Builder's in-progress edit of the selected theme. */
-export interface ThemeDraft {
+interface ThemeDraft {
   name: string;
   /** The config as editable JSON text (pretty-printed on load). */
   configText: string;
diff --git a/src/app/stores/DatasetStore.ts b/src/app/stores/DatasetStore.ts
index 7ef75bf..2183952 100644
--- a/src/app/stores/DatasetStore.ts
+++ b/src/app/stores/DatasetStore.ts
@@ -9,7 +9,7 @@
  * Two layers of action live here:
  *   - Low-level mutators (`add`/`update`/`remove`) are the single place the
  *     `datasets` array changes; the persistence subscriber writes them through to
- *     IndexedDB, and services (RelationshipService, future import) reuse them.
+ *     IndexedDB, and services (e.g. the import flow in services/transfer) reuse them.
  *   - Form orchestration (`save`) validates the form (name required + unique,
  *     data detectable) and turns it into an `add`/`update`, keeping the modal
  *     component thin.
@@ -31,7 +31,7 @@ import { isNameTaken } from '@core/naming';
 import { useSnippetStore } from './SnippetStore';
 
 /** Which pane the Datasets manager is showing (spec §05 → Layout). */
-export type DatasetView = 'list' | 'detail' | 'new' | 'edit';
+type DatasetView = 'list' | 'detail' | 'new' | 'edit';
 
 /** The in-progress create/edit form. `input` is the paste area (inline) or URL field. */
 export interface DatasetForm {
diff --git a/src/app/stores/ExtractStore.ts b/src/app/stores/ExtractStore.ts
index cda40b5..3393d22 100644
--- a/src/app/stores/ExtractStore.ts
+++ b/src/app/stores/ExtractStore.ts
@@ -31,7 +31,7 @@ interface InlineData {
  * none (no snippet, unparseable, or no `data.values`). The format comes from an
  * explicit `data.format.type` when present (raw CSV/TSV strings), else JSON.
  */
-export function readInlineData(draftText: string): InlineData | null {
+function readInlineData(draftText: string): InlineData | null {
   let parsed: unknown;
   try {
     parsed = JSON.parse(draftText);
diff --git a/src/app/stores/PanesStore.ts b/src/app/stores/PanesStore.ts
index de513f5..17c0c63 100644
--- a/src/app/stores/PanesStore.ts
+++ b/src/app/stores/PanesStore.ts
@@ -178,7 +178,7 @@ export function shownSideWidths(
 
 /** Per-pane visibility (spec §01A). Widths are kept *independently* of visibility,
  * so a hidden pane keeps its remembered width and re-shows at it (not a default). */
-export interface PaneVisibility {
+interface PaneVisibility {
   library?: boolean;
   editor?: boolean;
   preview?: boolean;
diff --git a/src/core/chart-builder.ts b/src/core/chart-builder.ts
index 4e9dd58..8e091f2 100644
--- a/src/core/chart-builder.ts
+++ b/src/core/chart-builder.ts
@@ -34,8 +34,7 @@ export const MARK_TYPES = ['bar', 'line', 'point', 'area', 'circle'] as const;
 export type MarkType = (typeof MARK_TYPES)[number];
 
 /** The four Vega-Lite field types a channel may carry, in override-menu order. */
-export const FIELD_TYPES = ['quantitative', 'nominal', 'ordinal', 'temporal'] as const;
-export type FieldType = (typeof FIELD_TYPES)[number];
+export type FieldType = 'quantitative' | 'nominal' | 'ordinal' | 'temporal';
 
 /** The four encoding channels the builder offers, in display order (spec §06). */
 export const CHANNELS = ['x', 'y', 'color', 'size'] as const;
@@ -49,8 +48,7 @@ export type ChannelName = (typeof CHANNELS)[number];
  * reduce a quantitative field; min/max also order a temporal or ordinal one. See
  * `validAggregateOps` for the per-type menu.
  */
-export const AGGREGATE_OPS = ['count', 'distinct', 'sum', 'mean', 'median', 'min', 'max'] as const;
-export type AggregateOp = (typeof AGGREGATE_OPS)[number];
+export type AggregateOp = 'count' | 'distinct' | 'sum' | 'mean' | 'median' | 'min' | 'max';
 
 /**
  * Temporal granularities (Vega-Lite `timeUnit`), coarse → fine, with the combined
@@ -71,12 +69,10 @@ export const TIME_UNITS = [
 export type TimeUnit = (typeof TIME_UNITS)[number];
 
 /** Sort the categorical axis by its measure (spec §06 → Ranking). */
-export const SORT_ORDERS = ['ascending', 'descending'] as const;
-export type SortOrder = (typeof SORT_ORDERS)[number];
+export type SortOrder = 'ascending' | 'descending';
 
 /** Part-to-whole stacking for bar/area + a colour series: absolute vs 100%. */
-export const STACK_MODES = ['zero', 'normalize'] as const;
-export type StackMode = (typeof STACK_MODES)[number];
+export type StackMode = 'zero' | 'normalize';
 
 /**
  * Comparison operators a guarded filter predicate offers (Vega-Lite field
@@ -85,17 +81,7 @@ export type StackMode = (typeof STACK_MODES)[number];
  * `range`; a category offers membership (`oneOf`). `notEqual` is expressed as a
  * `{ not: { …equal } }` logical wrapper (Vega-Lite has no bare `!=` predicate).
  */
-export const FILTER_OPS = [
-  'equal',
-  'notEqual',
-  'lt',
-  'lte',
-  'gt',
-  'gte',
-  'range',
-  'oneOf',
-] as const;
-export type FilterOp = (typeof FILTER_OPS)[number];
+export type FilterOp = 'equal' | 'notEqual' | 'lt' | 'lte' | 'gt' | 'gte' | 'range' | 'oneOf';
 
 /** How a filter expresses its predicate: a guarded shelf, or a raw expression. */
 export type FilterMode = 'predicate' | 'expression';
diff --git a/src/core/dataset.test.ts b/src/core/dataset.test.ts
index 56d0d76..0640c4b 100644
--- a/src/core/dataset.test.ts
+++ b/src/core/dataset.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, test } from 'vitest';
 import {
+  cellText,
   computeDatasetProfile,
   CURRENT_DATASET_VERSION,
   createDataset,
@@ -153,6 +154,17 @@ describe('tabularRows', () => {
   });
 });
 
+describe('cellText', () => {
+  test('strings as-is, null/undefined blank, others as JSON (no "[object Object]")', () => {
+    expect(cellText('plain')).toBe('plain');
+    expect(cellText(null)).toBe('');
+    expect(cellText(undefined)).toBe('');
+    expect(cellText(42)).toBe('42');
+    expect(cellText(false)).toBe('false');
+    expect(cellText({ a: 1 })).toBe('{"a":1}');
+  });
+});
+
 describe('snapshotFromText', () => {
   test('JSON content is parsed and typed json (content beats extension)', () => {
     const { data, format } = snapshotFromText('[{"a":1}]', 'https://x/data.txt');
diff --git a/src/core/dataset.ts b/src/core/dataset.ts
index 774aa54..8b4e69b 100644
--- a/src/core/dataset.ts
+++ b/src/core/dataset.ts
@@ -235,6 +235,16 @@ export function tabularRows(
   return limit != null && limit >= 0 && rows.length > limit ? rows.slice(0, limit) : rows;
 }
 
+/**
+ * Render a `tabularRows` cell for a preview table: strings as-is, null/undefined
+ * empty, anything else (numbers, booleans, nested values) as compact JSON.
+ */
+export function cellText(value: unknown): string {
+  if (value == null) return '';
+  if (typeof value === 'string') return value;
+  return JSON.stringify(value);
+}
+
 /**
  * Orchestrate profiling for a dataset payload: compute `size` (always), decide
  * tabular vs N/A by format, and delegate to `profileData`. Identical for inline
diff --git a/src/core/expr-validate.ts b/src/core/expr-validate.ts
index 3241a93..cf0c55f 100644
--- a/src/core/expr-validate.ts
+++ b/src/core/expr-validate.ts
@@ -9,8 +9,8 @@
  * grammar. It also extracts the `datum.<field>` references so the UI can flag a typo
  * against the dataset's actual columns before the chart silently renders empty.
  *
- * `vega-expression` is a pure dependency already in the bundle (Vega pulls it in for
- * rendering), so importing it here adds nothing and keeps this module browser-free.
+ * `vega-expression` is declared as a direct dependency but adds no bundle weight —
+ * Vega already ships it for rendering; this import reuses the same copy.
  */
 
 import { parseExpression } from 'vega-expression';
diff --git a/src/core/format-detection.ts b/src/core/format-detection.ts
index bce6b10..7c611b9 100644
--- a/src/core/format-detection.ts
+++ b/src/core/format-detection.ts
@@ -10,7 +10,7 @@
  */
 
 export type DataFormat = 'json' | 'csv' | 'tsv' | 'topojson';
-export type DetectionConfidence = 'high' | 'medium' | 'low';
+type DetectionConfidence = 'high' | 'medium' | 'low';
 
 export interface FormatDetection {
   format: DataFormat | null;
diff --git a/src/core/json-format.ts b/src/core/json-format.ts
index 9553331..b69ad31 100644
--- a/src/core/json-format.ts
+++ b/src/core/json-format.ts
@@ -12,7 +12,7 @@
 import stringify from 'json-stringify-pretty-compact';
 
 /** Width budget before an array/object wraps onto multiple lines. */
-export const DEFAULT_MAX_LINE = 80;
+const DEFAULT_MAX_LINE = 80;
 
 /** Default indent (spaces) — matches the editor's default tab size (spec §07). */
 const DEFAULT_INDENT = 2;
diff --git a/src/core/profile.ts b/src/core/profile.ts
index dd3c83b..32c894a 100644
--- a/src/core/profile.ts
+++ b/src/core/profile.ts
@@ -21,7 +21,7 @@
 
 import { inferColumnType, isEmpty, isNumeric, type ColumnType } from './type-inference';
 
-export interface ColumnTypeInfo {
+interface ColumnTypeInfo {
   /** The column name. */
   name: string;
   /** The inferred display type for the column. */
diff --git a/src/core/storage-estimate.ts b/src/core/storage-estimate.ts
index 7f96ba5..e9e0a81 100644
--- a/src/core/storage-estimate.ts
+++ b/src/core/storage-estimate.ts
@@ -16,7 +16,7 @@
  */
 
 /** A category of stored data and its measured size in bytes. */
-export interface StorageSegment {
+interface StorageSegment {
   key: 'snippets' | 'datasets' | 'app';
   /** User-facing label, centralized here so the component stays presentational. */
   label: string;
diff --git a/src/core/vega-themes.ts b/src/core/vega-themes.ts
index eacfc8e..1898820 100644
--- a/src/core/vega-themes.ts
+++ b/src/core/vega-themes.ts
@@ -181,7 +181,7 @@ const PRESET_IDS = [
   'dark',
 ] as const;
 
-export type ChartThemePresetId = (typeof PRESET_IDS)[number];
+type ChartThemePresetId = (typeof PRESET_IDS)[number];
 
 /** Empty config — the stock sentinel resolves to "inject nothing". */
 const STOCK_CONFIG: Config = {};