Mark M4 (Chart Builder) and M5 (Settings + Import/Export) done in the plan

docs/IMPLEMENTATION-PLAN.md

@@ -49,8 +49,8 @@ doc before implementing.
 | **M1.5** | Visual design foundation ✅ | Apply the design language: tokens, IBM Plex, restyled M1 surfaces, chart theme | [arch 09](architecture/09-visual-design.md) |
 | **M2**   | Editor robustness ✅        | Draft/Published, validation, schema autocomplete, fit modes                    | §03D–E, §04, §07(editor)                    |
 | **M3**   | Datasets ✅                 | Named reusable data + reference resolution in preview                          | §05, §03F, §09B                             |
-| **M4**   | Chart Builder               | No-JSON chart composition from a dataset                                       | §06                                         |
-| **M5**   | Settings + Import/Export    | Preferences + workspace backup/transfer                                        | §07, §08, §09C                              |
+| **M4**   | Chart Builder ✅            | No-JSON chart composition from a dataset                                       | §06                                         |
+| **M5**   | Settings + Import/Export ✅ | Preferences + workspace backup/transfer                                        | §07, §08, §09C                              |
 | **M6**   | Shell polish                | Resize/toggle panes, routing, shortcuts, toasts, a11y, offline                 | §01, §10                                    |
 
 **MVP boundary = end of M1** (a genuinely usable single-user chart authoring loop).
@@ -284,7 +284,7 @@ the reference.
 
 ---
 
-## M4 · Chart Builder
+## M4 · Chart Builder ✅ (done)
 
 **Goal:** no-JSON chart composition from a dataset → a new snippet.
 
@@ -326,6 +326,12 @@ and chose the **Tier B "smart + guarded"** design: smart default mark for the da
 valid-type-locked field-type menus, Size-channel discipline, and non-blocking guidance.
 The convergent rules and citations live in that doc; the spec (§06) was amended to match.
 
+**Verified:** `typecheck` + `test` green — the pure `chart-builder.ts` assembler
+(`chart-builder.test.ts`: mark/channel/type permutations, unmapped-channel omission,
+validation gate). The Chart Builder modal is wired through the registry, launched from a
+selected dataset (`DatasetsModal` → `openModal('chartBuilder')`). Data-aware
+cardinality/extent profiling + chart warnings landed (A3/A4).
+
 ---
 
 ## M4.5 · Snippet-library consolidation ✅ (done)
@@ -368,7 +374,7 @@ entries).
 
 ---
 
-## M5 · Settings + Import/Export
+## M5 · Settings + Import/Export ✅ (done)
 
 **Goal:** preferences and whole-workspace backup/transfer.
 
@@ -409,6 +415,12 @@ entries).
 - Change theme/debounce/date-format → takes effect; Cancel reverts; Reset confirms.
 - Export → reimport into a populated workspace merges without overwrite; renames reported.
 
+**Verified:** `typecheck` + `test` green — `import-normalize` (accepted shapes + merge/
+collision/rename), `export-envelope` (round-trip), `settings` (load-with-fallback),
+`UserSettingsStore`, `ux-prefs`. Distributed per-pane settings shipped as `SettingsPopover`
+disclosures (editor toolbar, preview, library) applying live; header Import/Export wired
+through `services/transfer.ts` (→ `normalizeImport` / envelope build), no modal.
+
 ---
 
 ## M6 · Shell polish & non-functional