be14a4bee3
Follow-up to the review on the session.resume ownership fix. Closing the
pre-transfer early returns left two gaps, both real.
1. The transfer had no owner on the other side. Once ownership moved to the
agent, teardown ran AIAgent.close() (via _teardown_session on session.close
and the orphaned-session reaper), which called session_db.end_session() —
that finalizes the session ROW, not the connection. A successfully resumed
profile session kept its dedicated handle, its db/-wal/-shm fds and its
background token-writer thread for the life of the gateway.
AIAgent now carries an explicit _owns_session_db, defaulting False so the
SHARED launch handle — which outlives every agent and backs every other live
session — is still never closed there. Only the dedicated-open sites set it,
at the point ownership actually changes hands.
2. session.resume was not the only profile-scoped open with no close on its
failure paths. Covered here with the same flag, via a _transfer_db_to_agent
helper that refuses the transfer unless the agent really holds that handle:
- the deferred builder (_start_agent_build), including the session-reaped-
mid-build case, where the built agent is discarded and never torn down, so
transferring to it would leak exactly as before;
- session.branch's branch_db;
- the compute host's per-profile open;
- AIAgent's own lazy open in _get_session_db_for_recall, which no other
object ever references and so was unconditionally abandoned.
Where a handle has already reached a registered session, the drop is
unconditional and the transfer is best-effort on top: a refused transfer leaves
the old leak, which is survivable, whereas closing under a live session is the
permanent "Cannot operate on a closed database" break the original patch exists
to avoid.
Tests: tests/tui_gateway/test_session_db_ownership_teardown.py (new, 14).
11 of the 14 fail without this change; the 3 that pass are the "must NOT close"
guards, which hold in both directions by design.