feat(subagents): make subagent timeout configurable via config.yaml (#897)

* feat(subagents): make subagent timeout configurable via config.yaml

- Add SubagentsAppConfig supporting global and per-agent timeout_seconds
- Load subagents config section in AppConfig.from_file()
- Registry now applies config.yaml overrides without mutating builtin defaults
- Polling safety-net in task_tool is now dynamic (execution timeout + 60s buffer)
- Document subagents section in config.example.yaml
- Add make test command and enforce TDD policy in CLAUDE.md
- Add 38 unit tests covering config validation, timeout resolution, registry
  override behavior, and polling timeout formula

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* feat(subagents): add logging for subagent timeout config and execution

- Log loaded timeout config (global default + per-agent overrides) on startup
- Log debug message in registry when config.yaml overrides a builtin timeout
- Include timeout in executor's async execution start log
- Log effective timeout and polling limit when a task is dispatched
- Fix UnboundLocalError: move max_poll_count assignment before logger.info

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* ci(backend): add lint step and run all unit tests via Makefile

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix lint

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/subagents/executor.py

@@ -343,7 +343,7 @@ class SubagentExecutor:
             status=SubagentStatus.PENDING,
         )
 
-        logger.info(f"[trace={self.trace_id}] Subagent {self.config.name} starting async execution, task_id={task_id}")
+        logger.info(f"[trace={self.trace_id}] Subagent {self.config.name} starting async execution, task_id={task_id}, timeout={self.config.timeout_seconds}s")
 
         with _background_tasks_lock:
             _background_tasks[task_id] = result

backend/src/subagents/registry.py

@@ -1,28 +1,46 @@
 """Subagent registry for managing available subagents."""
 
+import logging
+from dataclasses import replace
+
 from src.subagents.builtins import BUILTIN_SUBAGENTS
 from src.subagents.config import SubagentConfig
 
+logger = logging.getLogger(__name__)
+
 
 def get_subagent_config(name: str) -> SubagentConfig | None:
-    """Get a subagent configuration by name.
+    """Get a subagent configuration by name, with config.yaml overrides applied.
 
     Args:
         name: The name of the subagent.
 
     Returns:
-        SubagentConfig if found, None otherwise.
+        SubagentConfig if found (with any config.yaml overrides applied), None otherwise.
     """
-    return BUILTIN_SUBAGENTS.get(name)
+    config = BUILTIN_SUBAGENTS.get(name)
+    if config is None:
+        return None
+
+    # Apply timeout override from config.yaml (lazy import to avoid circular deps)
+    from src.config.subagents_config import get_subagents_app_config
+
+    app_config = get_subagents_app_config()
+    effective_timeout = app_config.get_timeout_for(name)
+    if effective_timeout != config.timeout_seconds:
+        logger.debug(f"Subagent '{name}': timeout overridden by config.yaml ({config.timeout_seconds}s -> {effective_timeout}s)")
+        config = replace(config, timeout_seconds=effective_timeout)
+
+    return config
 
 
 def list_subagents() -> list[SubagentConfig]:
-    """List all available subagent configurations.
+    """List all available subagent configurations (with config.yaml overrides applied).
 
     Returns:
         List of all registered SubagentConfig instances.
     """
-    return list(BUILTIN_SUBAGENTS.values())
+    return [get_subagent_config(name) for name in BUILTIN_SUBAGENTS]
 
 
 def get_subagent_names() -> list[str]: