docs(readme): fix emoji legend + fill quick start [skip-tdd: visual]

closes board-viewer-readme-emoji-fix

- Correct emoji set: ⚪ open / 🔴 in-progress / 🟡 paused / 🔵 blocked / 🟢 done
  (was ⚪/🟡/🟣/🔴/🟢 — pre-correction set from initial brainstorm)
- Filled TBD Quick start with npm test / typecheck / cli build / serve cmds
- Added Deploy + Architecture sections for new contributors

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

.tasks/STATUS.md

@@ -41,10 +41,10 @@ _Updated: 2026-05-22_
 
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-## ⚪ [board-viewer-readme-emoji-fix] — fix stale emoji legend in README.md
-**Status:** ready
-**Where I stopped:** review нашёл; trivial 1-line fix.
-**Next action:** обновить `README.md:5` на `⚪ open / 🔴 in-progress / 🟡 paused / 🔵 blocked / 🟢 done` + заполнить TBD "Quick start" блок.
+## 🟢 [board-viewer-readme-emoji-fix] — fix stale emoji legend in README.md
+**Status:** done
+**Where I stopped:** README обновлён: правильный emoji-словарь + Quick start заполнен + добавлены Deploy/Architecture секции.
+**Next action:** —
 **Branch:** master
 
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