feat(agent): core agent loop with asyncio, Claude API, tool dispatch, background thread

CLAUDE.md

@@ -68,7 +68,7 @@ Beads replaces `plan.md`. Same discipline, different storage:
 cd C:\projects\rook
 bd ready --json                                        # find unblocked tasks (start here)
 bd update <id> --claim                                 # mark in-progress before starting
-bd update <id> --status done                           # mark complete after commit + git note
+bd update <id> --status closed                         # mark complete after commit + git note
 bd create --title "..." --description "..."            # create a new task
 bd dep add <id> <depends-on-id>                        # link dependency
 bd list --json                                         # list all tasks
@@ -117,7 +117,7 @@ All work follows this strict lifecycle. **MMA tiered delegation is mandatory —
    git notes add -m "<task id> — <summary of changes and why>" <sha>
    ```
 
-8. **Mark done**: `bd update <id> --status done`
+8. **Mark done**: `bd update <id> --status closed`
 
 ### Worker Prompt Rules