feat(reader): Gitea client + config + board orchestrator

closes board-viewer-gitea-reader

- src/gitea.ts: HTTP client (getFile, getLatestCommitIso, rawUrl); DI'd fetch
- src/reader.ts: readBoard(client, repos) → TaskRecord[]
- src/config.ts: TOML config loader with board_viewer_repos whitelist
- 25 tests total (9 parser incl. 3 real-repo fixtures, 7 gitea, 5 reader, 4 config)
- emoji contract ⚪🔴🟡🔵🟢 (open/in_progress/paused/blocked/done)

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

package.json

@@ -16,5 +16,8 @@
     "@types/node": "^22.10.0",
     "typescript": "^5.7.0",
     "vitest": "^2.1.0"
+  },
+  "dependencies": {
+    "smol-toml": "^1.6.1"
   }
 }