feat: add in-chat skill discovery and local registry install command

docs/plans/state.json

@@ -5305,6 +5305,24 @@
         "docs/plans/state.json"
       ],
       "test_status": "pnpm test:run src/hooks/engine.test.ts src/commands/builtin/index.test.ts src/daemon/routing.test.ts src/tools/executor.test.ts + pnpm typecheck passing"
+    },
+    "skill-discovery-in-chat-tier-b4": {
+      "status": "completed",
+      "date": "2026-02-18",
+      "updated": "2026-02-18",
+      "summary": "Completed Tier B4 in-chat discovery/install surface by adding `/skill` command (`list|search|install`) through command fast-path. Reused existing registry source/catalog infrastructure and managed-skill installer, with local registry-source install support and explicit remote-source fallback guidance to CLI.",
+      "files_modified": [
+        "src/commands/types.ts",
+        "src/commands/builtin/index.ts",
+        "src/commands/builtin/index.test.ts",
+        "src/commands/index.ts",
+        "src/daemon/routing.ts",
+        "src/daemon/routing.test.ts",
+        "src/daemon/index.ts",
+        "README.md",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/commands/builtin/index.test.ts src/daemon/routing.test.ts + pnpm typecheck passing"
     }
   },
   "overall_progress": {
@@ -5328,7 +5346,7 @@
     "gmail_auth_cli": "flynn gmail-auth command implemented with OAuth2 flow, doctor check, config routed to Telegram",
     "native_audio_support": "completed — smart routing for native audio (Gemini/OpenAI/GitHub) vs Whisper transcription fallback",
     "remaining_phases_completion": "Phase 1: 3/3 (100%) — context levels, command registry, memory structure. Phase 2: 3/3 (100%) — component registry, confidence routing, history index. Phase 3: 2/2 (100%) — adaptive memory/compaction, truthfulness/autonomy hardening",
-    "next_up": "Implement Tier B4 skill discovery index (registry-backed search/install flow)"
+    "next_up": "Implement Tier B3 progressive web app push notifications for WebChat"
   },
   "soul_md_and_cron_create": {
     "date": "2026-02-11",