refactor(plugin): remove SessionStart as the primary Tiny Actor council surface

- Remove render_actor_preview("PLAN") call block from session-start.py
- Delete test_session_start_actors.py integration tests (no longer needed)
- Tiny Actor library code and unit tests preserved for request-driven reuse

Closes #1362

Author: JeremyDev87

packages/claude-code-plugin/hooks/session-start.py

@@ -947,16 +947,6 @@ def main():
             if output:
                 print(output)
 
-            # Tiny Actor Grid preview (#1302)
-            try:
-                from tiny_actor_preview import render_actor_preview
-
-                actor_preview = render_actor_preview("PLAN")
-                if actor_preview:
-                    print(actor_preview)
-            except Exception:
-                pass  # Never block session start
-
             # Show update notification if marketplace clone was updated (#1101)
             if new_version:
                 print(