feat(engine): finding + findings-summary surfaces — review-findings loop unified

[leeovery]

Stage 2 of the render-surfaces programme (design log: #489; base: #490). The findings/approval family: one surface pair now serves both review-findings loops — workflow-planning-process and workflow-specification-process carried near-identical ~240-line reference twins whose displays, frames, and gate menus all now come from the engine.

Surfaces

render findings-summary <wu>.<phase>.<topic> --file <payload> — the numbered overview ({review_label} — N items found), summaries in the · subsection grammar, and the working-through line, one section.

render finding <wu>.<phase>.<topic> --file <payload> — one finding end-to-end:

• DISPLAY: finding — title, [label, value] meta pairs (each consumer's own vocabulary), details.
• The proposal, either as DISPLAY: finding content (markdown, full content) or as the framed diff in three sections — frame open, diff body emitted as a ```diff fence (colouring survives), frame close. Borders computed from actual content width (the Portal defect, fixed user-visibly) and capped at 100 so a border never wraps; unwrappable diff lines may overflow past the cap.
• The gate: MENU: finding gate when finding_gate_mode is gated (with v/view full offered only for diff findings) or DISPLAY: finding auto-approved when auto — per-consumer apply/applied/feedback labels ride in the payload.

Contract notes: tracking files are markdown, so per D2 the model reads them and hands validated JSON (11 loud validation cases); the gate-mode read and branch left both prose files entirely.

Test plan

• 12 new tests: byte-exact summary, gated diff render (frame min-width, view-full presence), maxWidth border cap, content+auto variant, loud validation for both surfaces.
• npm test — 1485/1485. Typecheck + conventions lint clean.

🤖 Generated with Claude Code

Stack

1. feat(engine): discovery-map add-batch + cache purge at close (D7 one-call) #495
2. feat(engine): render surface catalogue — resume-gate and task-list pilots #490
3. feat(engine): finding + findings-summary surfaces — review-findings loop unified #491 👈 current
4. feat(engine): task-gate surfaces — proposed-task, tasks-overview, author-task-gate, phase-tree #492
5. feat(engine): selection projection + bridge continuation surfaces #493
6. feat(engine): transaction confirmation sections — lifecycle verbs carry their own chrome #496
7. feat(engine): entry-gate + phase-note — entry validation derives engine-side #497
8. feat(engine): the fence is the frame — boxedFrame retired (D8) #498
9. feat(engine): topic complete + discovery-session close fold their kb warnings (7a) #499
10. feat(engine): resume-gate variants + entry-gate --own + phase-completed --paths (7b) #500
11. test(conventions): templated-fence ratchet — check 13 lands D4 (7c) #501