Keep Git status and diffs current across platforms (#2775)

* fix(server): make Git observation cross-platform

Platform-specific watchers and forced full refreshes amplified Git processes and could miss nested changes. Share checkout and repository observation internally, scope final-state refreshes, and bound degraded polling so streamed summaries and diffs stay correct under bursts.

* fix(server): refresh Git worktree state on metadata changes

* fix(server): keep Git watcher runtime inputs current

* fix(server): normalize watcher runtime boundaries

* fix(server): reconcile Git observer topology

* test(server): report Git watcher event batches

* fix(server): close Git observation gaps

* chore(ci): remove temporary Git observation jobs

packages/server/package.json

@@ -45,6 +45,7 @@
     "typecheck": "tsgo -p tsconfig.server.typecheck.json --noEmit",
     "generate:config-schema": "tsx scripts/generate-config-schema.ts",
     "measure:agent-tools": "tsx scripts/measure-agent-tools-context.ts",
+    "measure:git-observation": "tsx scripts/measure-git-observation.ts",
     "speech:models": "tsx scripts/list-speech-models.ts",
     "speech:download": "tsx scripts/download-speech-models.ts",
     "speech:transcribe:local": "tsx scripts/transcribe-local-wav.ts",
@@ -75,6 +76,7 @@
     "@isaacs/ttlcache": "^2.1.4",
     "@modelcontextprotocol/sdk": "^1.20.1",
     "@opencode-ai/sdk": "1.14.46",
+    "@parcel/watcher": "^2.6.0",
     "@xterm/headless": "^6.0.0",
     "ai": "5.0.78",
     "ajv": "^8.20.0",