Story-2281: the section reading surface (B4, EPIC-2270)

The backend now knows what the parts of a document ARE — cause title, grounds, prayer — and stores each as a typed range over (page, block) pairs (RFD-DOC-004, functions #647/#648/#649). This ticket is the half counsel can see: the outline that lists those parts, the gutter that says what is attached to each, the box that draws one across a page break, the machine copy that speaks the same coordinates, and the two acts counsel has over the machine's read.

The idea in one line

The section is the only anchor. A note keeps the span it always had (page + block + byte-exact quote, Story-2116); its enclosing section is derived by range containment at render — never a stored foreign key. That is what lets a re-segmentation move every mark without touching a single note, and what lets an OCR-scanned photocopy with no printed paragraph numbers anchor exactly like a born-digital pleading.

What was built

Two decisions worth naming

• Optimistic curation went into the helper layer, not the component. Keep/Dismiss needed an onMutate/rollback. Rather than hand-roll one in the viewer, this adds optimisticCollectionPatch() beside the existing optimisticCollectionInsert() in src/lib/query/invalidation.ts — the sibling for writes that EDIT a row rather than add one. Any future in-place write (a flag toggle, a rename) inherits it. keep doubles as the undo of a dismissal, because returning the annotation to active is exactly what restoring a dismissed mark means.
• The section box is computed, not stored. D3 says geometry by reference: the box is the union of the bounding boxes of the blocks inside the section's range on that page, unioned at render. If the blocks cannot be resolved, NO box is drawn — never a guessed rectangle.

Live evidence (staging, 2026-07-12)

Verified end-to-end against real staging data (local app → staging gateway → staging Postgres), on document 2ff05fda-426c-4701-8de4-c8013844100a in matter M-015:

• GET .../sections → 200 through the new proxy + contract assert.
• GET /documents/{id}/blocks → 200; the machine copy renders the real extracted text.
• POST .../re-read → {"queued": true} from staging functions; the button showed its pending state and the JOURNEY rendered from real status events.
• Outline drew the sections with derived ordinals and the ● human-boundary dot; selecting the cross-page section produced data-section-edge="first" on page 1 and "last" on page 2 (SS-02).
• A real note posted through the annotations API appeared with its DERIVED enclosing-section chip ("Movement") and a gutter mark at that section's position, whose popover listed it with its byte-verified quote.

Verification

• pnpm lint · pnpm test (1106 passing) · pnpm build · pnpm check:routes · pnpm storybook:check — all green.
• Every new component ships a co-located story; the outline's collapse/expand and the popover's curate/undo are interactive so a reviewer can replay them.
• i18n: every new key exists in en and hi (parity asserted programmatically). Tokens only — the color-literal grep is clean over the changed files.