session-memory Phase 1: Grok adapter (T02)

- adapters/grok.py: reads the per-session dir (summary.json + chat_history.jsonl
  + events.jsonl + updates.jsonl); conversation from chat_history, lifecycle/
  turn from events, tool-call names paired in order from updates ACP stream
- registered in ingest dispatch; codex+grok sources enabled in config.toml
- tests/test_grok_adapter.py (synthetic + real local sessions)
- live multi-flavor dry-run discovers 89 sessions across flavors

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

session_memory/ingest.py

@@ -20,6 +20,7 @@ from typing import Any
 
 from .adapters import claude as claude_adapter
 from .adapters import codex as codex_adapter
+from .adapters import grok as grok_adapter
 from .core import digest as digest_mod
 from .core.cursor import Cursors
 from .core.retention import RetentionConfig, sweep as retention_sweep
@@ -29,6 +30,7 @@ from .core.store import Store
 _ADAPTERS = {
     "claude": claude_adapter.parse_session,
     "codex": codex_adapter.parse_session,
+    "grok": grok_adapter.parse_session,
 }