Publicize Dispatcher.executor (remove private-attribute cross-module access)

Task 5 from pr-21-fixes.md:

- Rename Dispatcher._executor → Dispatcher.executor (public attribute)
- __main__.py updated to use dispatcher.executor instead of dispatcher._executor

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

Author: coordt

foreman/__main__.py

@@ -164,7 +164,7 @@ def _run_start(args: Any) -> None:
 
         # Expose shared state for the lifespan background loops.
         app.state.task_queue = task_queue
-        app.state.executor = dispatcher._executor
+        app.state.executor = dispatcher.executor
         app.state.memory = memory
         app.state.config = config
 

foreman/server.py

@@ -53,7 +53,7 @@ def __init__(self, config: ForemanConfig, memory: MemoryStore, task_queue: TaskQ
         self._config = config
         self._memory = memory
         self._task_queue = task_queue
-        self._executor = GitHubExecutor(token=str(config.identity.github_token), memory=memory)
+        self.executor = GitHubExecutor(token=str(config.identity.github_token), memory=memory)
 
     async def dispatch(self, event: dict[str, Any], route_target: RouteTarget) -> None:
         """Enqueue *event* for the agent described by *route_target* and nudge it.