feat(04-01): finalize AgentApi migration

.planning/phases/04-matrix-mvp-shared-agent-context-and-context-management-comma/04-01-SUMMARY.md

@@ -0,0 +1,29 @@
+# 04-01 Summary
+
+## Outcome
+
+Replaced the Matrix real backend's custom `AgentSessionClient` path with a shared
+`AgentApiWrapper` over upstream `lambda_agent_api.AgentApi`.
+
+## Changes
+
+- Added `sdk/agent_api_wrapper.py` to capture `MsgEventEnd.tokens_used` without
+  modifying `external/`.
+- Rewrote `sdk/real.py` to use a shared `agent_api`, stream text chunks from
+  `AgentApi.send_message()`, and emit a final `MessageChunk` with
+  `last_tokens_used`.
+- Updated `adapter/matrix/bot.py` to construct `RealPlatformClient` with
+  `AgentApiWrapper`, keep `AGENT_WS_URL` unchanged, and manage
+  `agent_api.connect()` / `agent_api.close()` around `sync_forever()`.
+- Stubbed `sdk/agent_session.py` as a compatibility placeholder.
+- Updated Matrix/runtime tests away from `thread_key` and per-request websocket
+  assumptions.
+
+## Verification
+
+- `pytest tests/platform/test_real.py -q`
+- `pytest tests/adapter/matrix/test_dispatcher.py -q`
+- `pytest tests/core/test_integration.py -q`
+- `pytest tests/platform/test_agent_session.py -q`
+
+All listed commands passed locally.