serve: board UI — six lanes + card faces + post-it styling

[andreiRS]

Part of the serve-board spec (docs/specs/serve-board.md), architecture in docs/adr/0016-board-server-reuses-core-in-process.md.

Effort

L — the main UI surface and visual style.

What to build

The board UI: render GET /api/board as six lanes (horizontal scroll) of post-it cards in the handwritten / physical-sticky-note style of the reference prototype. Each card face shows: Short ID pill, handwritten title, ~2-line body preview, effort as a corner color dot, a red "blocked by #N" badge when the task has unresolved blockers (in any lane), an attended/agent marker, and "updated Xm ago". Card paper color and tilt are seeded from the task id (stable across refresh). Read-only in this slice (no drag/create/edit yet). Left rail collapses to just a logo mark; no search/filter toolbar.

Acceptance criteria

• All six lanes render with cards sorted oldest-first; counts per lane are correct.
• Card face shows id, title, body preview, effort dot, blocked-by badge (when applicable), attendance marker, updated-ago.
• Color and tilt are stable per task across reloads (seeded from id).
• Empty lane shows the quiet handwritten dashed drop-zone state.

Blocked by

#13, #25

[andreiRS]

Done on feat/serve-board — commit efe1cb9 (green: board UI — six lanes + post-it card faces).

Read-only six-lane board over GET /api/board: post-it cards with id→color+tilt seeding (deterministic FNV-1a, decorrelated), short-id pill, handwritten title, 2-line body preview, effort dot, red "blocked by #N" badge, attendance marker (human/agent), "updated Xm ago", and a dashed drop-zone for empty lanes. Collapsed logo rail, no toolbar.

Verification (per the browser-only testing decision for this slice — no Vitest): root + web tsc --noEmit clean, vite build clean, and a real-browser pass against a seeded store confirmed all six lanes, correct counts (2/2/1/0/1/1), the blocked-by badge on #4→#3, the empty-lane drop-zone, and post-it styling. Code-reviewed (verdict: ship; one forward-looking note carried to #20 about guarding overlapping snapshot loads).

Drag (#19), SSE live sync (#20), create modal (#21), drawer (#22) build on this and are not included here.