fix(python-client): async method parity and server keepalive timeout

[cdbartholomew]

Summary

• Server keepalive fix: Set uvicorn timeout_keep_alive to 30s. The default (5s) is shorter than aiohttp's client-side keepalive (15s), causing ServerDisconnectedError when the client reuses a connection the server has already closed.
• Async method parity: arecall() was missing 6 parameters available in recall() (trace, query_timestamp, include_entities, include_chunks, max_entity_tokens, max_chunk_tokens) and returned list[RecallResult] instead of RecallResponse. areflect() was missing max_tokens and response_schema.
• New async methods: Added acreate_bank(), aset_mission(), and adelete_bank() — previously only available as sync.

Breaking change: arecall() return type

arecall() now returns RecallResponse instead of list[RecallResult].

This is a bug fix, not a design decision. The old arecall() was an incomplete implementation that:

1. Silently discarded data — it stripped trace, entities, and chunks from the response by only returning response.results
2. Couldn't support features — there was no way to request or receive chunks/entities, making the async path functionally inferior to the sync API
3. Didn't match its own sync counterpart — the sync recall() has always returned RecallResponse, so anyone switching from sync to async would hit a different return type

The return type was wrong from day one relative to the sync API and the underlying OpenAPI spec. As a 0.x library, semver explicitly allows breaking changes before 1.0.

Migration is trivial:

# Before
memories = await client.arecall(bank_id, query)
for m in memories:

# After
response = await client.arecall(bank_id, query)
for m in response.results:

Test plan

• New unit test verifies uvicorn config has timeout_keep_alive > 15
• New async integration tests for arecall (5 tests: return type, include_chunks, include_entities, trace, all params)
• New async integration tests for areflect (2 tests: max_tokens, structured output)
• New async integration test for adelete_bank
• All existing tests pass (36/36, excluding pre-existing flaky test_recall_with_tags_any)
• Pre-commit lint hooks pass