feat: wire agent.delegate tool with sub-agent configs

- Export createAgentDelegateTool through builtin/index.ts → tools/index.ts
- Register agent.delegate in routing.ts with lazy orchestrator pattern
- Add agent.delegate + agents.list to messaging and coding policy profiles
- Add group:agents tool group to policy.ts
- Add research/code/comms agent config examples to default.yaml
- Add research/code/comms agent configs to user config.yaml
- Add 11 tests for agent-delegate tool (all pass)
- Typecheck clean, no regressions

docs/plans/state.json

@@ -3560,6 +3560,40 @@
         "docs/plans/state.json"
       ],
       "test_status": "pnpm test:run src/backends/native/orchestrator.test.ts src/config/schema.test.ts src/gateway/handlers/agent.test.ts src/gateway/handlers/handlers.test.ts src/gateway/protocol.test.ts src/commands/builtin/index.test.ts src/frontends/tui/commands.test.ts src/frontends/tui/minimal.test.ts + pnpm typecheck passing"
+    },
+    "line-zalo-outbound-attachment-forwarding": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Updated LINE and Zalo adapters to preserve attachment-only outbound sends, forward URL attachments as chat lines, and emit explicit warnings for binary payloads that still require provider-specific upload implementations.",
+      "files_modified": [
+        "src/channels/line/adapter.ts",
+        "src/channels/line/adapter.test.ts",
+        "src/channels/zalo/adapter.ts",
+        "src/channels/zalo/adapter.test.ts",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/channels/line/adapter.test.ts src/channels/zalo/adapter.test.ts + pnpm typecheck passing"
+    },
+    "external-backend-codex-gemini-routing": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Added external CLI backend support for `codex` and `gemini` (alongside `claude_code`/`opencode`) with configurable command args/timeouts, daemon wiring, per-agent backend selection, `/status` backend visibility, and native fallback when external execution fails.",
+      "files_modified": [
+        "src/backends/external.ts",
+        "src/backends/index.ts",
+        "src/config/schema.ts",
+        "src/config/schema.test.ts",
+        "src/agents/registry.ts",
+        "src/agents/registry.test.ts",
+        "src/daemon/index.ts",
+        "src/daemon/routing.ts",
+        "src/daemon/routing.test.ts",
+        "config/default.yaml",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/agents/registry.test.ts src/config/schema.test.ts src/daemon/routing.test.ts + pnpm typecheck passing"
     }
   },
   "overall_progress": {