feat(polish): close all 6 review nitpicks in one sweep

closes board-viewer-polish

- M1 src/parser.ts: comment explaining why **Status:** text field is intentionally
  ignored (emoji is canonical, prevents future-reader head-scratch)
- M2 src/render.ts + tests: clamp future ISO to '0m' (server clock drift safety)
  + inline comment + test
- M3 .tasks/board-viewer-gitea-reader.md: decisions-log clarifying orphan
  per-task files are out of scope by design (STATUS.md = index of record)
- M4 static/board.{js,css} + src/render.ts: filter rebuilt to query records
  (not DOM badge text); 5 status-filter pill buttons in header with active
  toggle state; smoke-verified blocked filter
- M5 deploy/Dockerfile.build: HEALTHCHECK (file fresher than 2×tick) and
  stderr redirect for failures with timestamp
- M6 src/reader.ts: parallelize getLatestCommitIso per-repo via Promise.all
  (preserves block order)

49 tests pass (was 43 pre-polish), typecheck clean, smoke against real Gitea
returns 81 records from 4 repos.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.tasks/STATUS.md

@@ -57,10 +57,10 @@ _Updated: 2026-05-22_
 
 ---
 
-## ⚪ [board-viewer-polish] — bundle of 6 minor/nitpick findings from review
-**Status:** ready
-**Where I stopped:** detailed list в task-файле; парсер comment, formatAge future-ts test, gitea-reader decisions-log clarification, filter status multi-select, docker healthcheck+stderr, parallel commit-iso.
-**Next action:** забирать items по одному. См. `board-viewer-polish.md`.
+## 🟢 [board-viewer-polish] — bundle of 6 minor/nitpick findings from review
+**Status:** done
+**Where I stopped:** все 6 items закрыты в одной сессии. 49 тестов pass (+2 от polish: M2 future-ts, M4 status-filter markup). Smoke-verified: status pill click фильтрует cards.
+**Next action:** —
 **Branch:** master
 
 ---