session-memory Phase 0: normalized schema (T01) + Claude adapter (T02)

- session_memory/core/schema.py: Session/SessionEvent/Cost dataclasses,
  flavor-prefixed uids, watermarks, kind/outcome validation (T01)
- session_memory/adapters/claude.py: JSONL -> Normalized bundle, turn DAG
  via uuid/parentUuid, kind mapping, cost from message.usage (T02)
- tests: schema round-trip + adapter (synthetic + real local session)

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

workplans/AGENTIC-WP-0002-session-memory-phase0.md

@@ -28,7 +28,7 @@ adapters land in Phase 1.
 
 ```task
 id: AGENTIC-WP-0002-T01
-status: todo
+status: done
 priority: high
 state_hub_task_id: "61297a16-257c-4579-bd1f-3db035781258"
 ```
@@ -42,7 +42,7 @@ round-trip (de)serialization tests. This is the contract every adapter targets.
 
 ```task
 id: AGENTIC-WP-0002-T02
-status: todo
+status: done
 priority: high
 state_hub_task_id: "3b4e6b35-b4f3-40dc-a845-7ac78aa20d62"
 ```
@@ -58,7 +58,7 @@ Codex/Grok work in Phase 0 (designed for, not built).
 
 ```task
 id: AGENTIC-WP-0002-T03
-status: todo
+status: progress
 priority: high
 state_hub_task_id: "2387258e-ba6d-4a41-919e-f2f4e0822110"
 ```