Chart builder: discoverable entry points — Build Chart door, dataset picker, no-datasets state

docs/chart-builder-enhancement-scope.md

@@ -25,6 +25,34 @@
 Newest first. The at-a-glance build-order tracker is §4; per-item detail is §3. This log is
 the quick "where are we" — read it first.
 
+- **2026-06-12 (3D)** — **entry points & discoverability shipped. Up next: 3A (the
+  front door now has somewhere to be found).**
+  - **Library creation surface forked:** primary **Build Chart** (accent, takes the
+    slack) + ghost **New JSON snippet** (the old instant create) — two plain buttons,
+    no menu widget; labels collapse in two stages as the pane narrows (the long ghost
+    label first). New `chart` icon (rising columns, pane-icon rect style).
+  - **The builder opens un-targeted:** `init(null)` picks the most recently modified
+    dataset; a **Dataset picker** heads the config pane (replaces the "Building from"
+    line). Switching with an untouched config re-derives smart defaults; a built-on
+    config is **rebased** via the new core `rebaseBuilderConfig` (mark/title/size/
+    sort/stack/calculates/expression-filters kept; encodings + predicate filters bound
+    to columns the new dataset lacks shed; same-schema switch keeps everything).
+  - **No-datasets state** (Carbon no-data): what the builder does + primary "Add a
+    dataset" → Datasets create form. A defensive "Choose a dataset" chooser covers the
+    datasets-exist-but-none-loaded case. New `#build` hash serializes the
+    no-dataset builder (spec §01E table).
+  - **Onboarding gains the data-first door** ("Build a chart from your data", ghost
+    beside the primary; applies the workspace split up front since the builder can
+    create the first snippet). Dataset-row "Build Chart" unchanged (the contextual
+    shortcut).
+  - **Contract updated:** spec §02 (creation surface, onboarding), §06 (Opening
+    rewritten: doors, dataset picker, no-datasets state), §01E (`#build`); council
+    resolutions recorded in `architecture/10` §5 ("builder-forward, Monaco-intact").
+  - **Verified:** `typecheck` + `test` (873, +10: core rebase, store init(null)/
+    switchDataset, url-hash `#build`, modal empty states) + `eslint` + prettier.
+    **Owed:** a visual pass on the forked creation surface + builder picker/empty
+    states (user-driven, batched with the 2B visual debt).
+
 - **2026-06-12 (polish batch)** — **the 2B visual-pass findings fixed; the parked council
   batch resolved and applied; two capability gaps closed.**
   - **Aggregation for any field type.** `validAggregateOps` replaces the quantitative-only
@@ -400,7 +428,7 @@ builder only creates) and the disabled-button affordance (disabled-with-reason v
 park in `ux-second-pass.md` if non-obvious). _Spec impact: §02 (library row action) + §06
 (hydration + the strict gate)._
 
-**3D · Entry points & discoverability** — _decided 2026-06-12, council-reviewed; lands with or just before 3A_
+**3D · Entry points & discoverability** — _done 2026-06-12 (council-reviewed; see status log); 3A opens onto it next_
 Today the builder has **one entry, two levels deep**: Datasets modal → per-dataset "Build
 Chart" (`DatasetsModal.tsx`) — the data model's shape ("charts come from datasets"), not
 the user's intent ("I want to make a chart"). Meanwhile the library's pinned primary
@@ -423,9 +451,11 @@ The decided shape:
    ghost/tertiary **New JSON snippet** (today's instant create, unchanged). Two plain
    buttons with clear hierarchy — no split/menu-button widget (two static choices don't
    earn an ARIA menu).
-2. **Dataset picker inside the builder** (header select, default = most recently used), so
-   the builder opens without a preselected dataset. Build-time detail: switching datasets
-   mid-build re-derives smart defaults vs. prunes incompatible encodings — decide then.
+2. **Dataset picker inside the builder** (header select, default = most recently
+   modified), so the builder opens without a preselected dataset. Build-time decision
+   taken: switching with an **untouched** opening config re-derives fresh smart defaults;
+   switching a **built-on** config rebases it (`rebaseBuilderConfig` — chart-level intent
+   kept, bindings to missing columns shed; a same-schema dataset keeps everything).
    Useful beyond 3D (switch data without leaving the builder).
 3. **No-datasets empty state** in the builder, per the Carbon no-data pattern: what the
    builder does + one primary action ("Add a dataset" → Datasets modal). No dead end.
@@ -526,8 +556,8 @@ Phase 1  1A actionable hints      ✓ done
          1E expr-validate         ✓ done (syntax + unknown-field; completion popup deferred)
 Phase 2  2A value-or-field channels (Property model)  ✓ done
          2B field shelf + in-place type cycling       ✓ done (field-first + on-chart shelves)
-Phase 3  3D entry points & discoverability         ← next, with/just before 3A (its prerequisite)
-         3A intent-first front door (Tier C)       ← built on 2B; the defining feature
+Phase 3  3D entry points & discoverability         ✓ done (2026-06-12)
+         3A intent-first front door (Tier C)       ← next; built on 2B; the defining feature
          3B starter examples
          3C open in builder (strict hydration)     ← added 2026-06-11; pairs with 3B
 Phase 4  (gated) theta/facets/styling-overrides/undo/lookup — decide after Phase 3