feat: v2 plan — remove autogen/crewai, add tasks and wiki

- Remove autogen and crewai backends (focus on custom only)
- Simplify CLI: remove --backend flag
- Remove optional deps from pyproject.toml
- Add .tasks/ with 7 tasks for Phase 1 refactor
- Add .wiki/concepts/meeting-room-v2.md with architecture plan
- Update .wiki/index.md and .tasks/STATUS.md

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

meeting_room/cli.py

@@ -223,7 +223,7 @@ def find_workspace_config() -> str | None:
     return None
 
 
-def run_discussion(backend: str, scenario: str, config: dict, save: bool = False):
+def run_discussion(scenario: str, config: dict, save: bool = False):
     scenario_path = scenario if os.path.isabs(scenario) else os.path.join(os.getcwd(), scenario)
     if not os.path.exists(scenario_path):
         # Try bundled scenarios
@@ -232,18 +232,8 @@ def run_discussion(backend: str, scenario: str, config: dict, save: bool = False
         print(f"Scenario not found: {scenario}")
         sys.exit(1)
 
-    if backend == "custom":
-        from meeting_room.backends.custom.run import run
-        conversation = run(scenario_path, config)
-    elif backend == "autogen":
-        from meeting_room.backends.autogen.run import run
-        conversation = run(scenario_path, config)
-    elif backend == "crewai":
-        from meeting_room.backends.crewai.run import run
-        conversation = run(scenario_path, config)
-    else:
-        print(f"Unknown backend: {backend}")
-        sys.exit(1)
+    from meeting_room.backends.custom.run import run
+    conversation = run(scenario_path, config)
 
     if save and conversation:
         # Determine sessions dir
@@ -263,12 +253,6 @@ def main():
     parser = argparse.ArgumentParser(
         description="Meeting Room — Multi-Agent Discussion Framework",
     )
-    parser.add_argument(
-        "-b", "--backend",
-        choices=["custom", "autogen", "crewai"],
-        default="custom",
-        help="Discussion framework (default: custom)",
-    )
     parser.add_argument(
         "-s", "--scenario",
         default="example-saas.md",
@@ -336,7 +320,7 @@ def main():
     if args.workdir:
         config["defaults"]["workdir"] = args.workdir
 
-    run_discussion(args.backend, args.scenario, config, save=args.save)
+    run_discussion(args.scenario, config, save=args.save)
 
 
 if __name__ == "__main__":