Add eval harness (#62 P4), status frames (#96), and agentic runs (#63).

Ship the Phase 4 accuracy eval suite with a manual Gitea workflow, emit
versioned WS status frames during grounded chat, and introduce opt-in
agent infrastructure (Redis/Celery, AgentRun/Step, tools, orchestrator)
gated by ALLOW_AGENTIC_TASKS so default chat behaviour stays unchanged.

pyproject.toml

@@ -49,6 +49,11 @@ dependencies = [
     "python-dateutil==2.9.0.post0",
     "pytz==2025.2",
     "stripe>=12.0.0,<14.0.0",
+    # Agentic task execution (#63): Redis-backed channel layer for multi-worker
+    # progress fan-out, plus Celery for durable long-running agent runs.
+    "channels-redis==4.3.0",
+    "redis==6.4.0",
+    "celery==5.5.3",
 ]
 
 [dependency-groups]