docs(councils): add quickstart, API doc, and state tracking

docs/plans/state.json

@@ -1,6 +1,6 @@
 {
   "version": "1.0",
-  "updated_at": "2026-02-19",
+  "updated_at": "2026-02-21",
   "description": "Tracks the status of all Flynn plans and implementation phases",
   "plans": {
     "faster-inflight-cancel-propagation": {
@@ -5893,6 +5893,35 @@
         "docs/plans/state.json"
       ],
       "test_status": "pnpm test:run src/tools/builtin/minio-sync.test.ts + pnpm typecheck passing"
+    },
+    "councils-dual-group-orchestrator": {
+      "status": "completed",
+      "date": "2026-02-21",
+      "updated": "2026-02-21",
+      "summary": "Implemented deterministic dual-council orchestration (D/P) with strict JSON artifacts, bridge-only exchange, deterministic ID allocation and canonical hashing, code-side brief diffs, bridge cap enforcement, and deterministic meta merge constraints. Added council.run tool + /council command wiring, config schema/defaults, docs, and focused test coverage (including leakage and bridge fail-closed paths).",
+      "files_modified": [
+        "src/councils/canonical.ts",
+        "src/councils/types.ts",
+        "src/councils/orchestrator.ts",
+        "src/councils/index.ts",
+        "src/tools/builtin/council-run.ts",
+        "src/tools/builtin/council-run.test.ts",
+        "src/tools/builtin/index.ts",
+        "src/tools/index.ts",
+        "src/tools/policy.ts",
+        "src/commands/types.ts",
+        "src/commands/builtin/index.ts",
+        "src/commands/builtin/index.test.ts",
+        "src/config/schema.ts",
+        "src/config/schema.test.ts",
+        "src/config/index.ts",
+        "src/daemon/routing.ts",
+        "config/default.yaml",
+        "README.md",
+        "docs/api/COUNCILS.md",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/councils/orchestrator.test.ts src/tools/builtin/council-run.test.ts src/commands/builtin/index.test.ts src/config/schema.test.ts src/daemon/routing.test.ts src/tools/policy.test.ts + pnpm typecheck passing"
     }
   },
   "overall_progress": {