fix(integrations): stop posting the model's closing text after band_no_reply or band_send_message

[bandzalkin]

Problem

RoomTurnEmitter relays the model's closing text unless turn_replied_in_room() sees a completed band_send_message/band_no_reply in the ACP stream — matched by the tool_call title (ACPToolCall.from_acp reads title first).

On OMP that never matches:

• OMP fills the title with the model's i intent phrase (buildToolTitle in modes/acp/acp-event-mapper.ts), e.g. "Ending the turn silently".
• Without an intent, OMP names MCP tools mcp__band_<tool>, a spelling _resolve_mcp_tool_name does not accept.

So every OMP turn's closing narration was posted to the room as a reply to the sender being answered. Observed live (band-agent, SDK 3.3.0): two OMP agents looped for ~10 minutes, one posting "X's message asks nothing new of me, so I ended the turn without replying. Task 2 is at …" every ~10 s — the runner log shows no reply this turn at the same timestamps — each post starting the other agent's next turn. Real band_send_message calls were also duplicated by their narration ("I told the architect…").

Fix

• engine.py / backends.py: the http/sse local MCP backend now honors tool_result_hook (the Claude backend already had one; the http path silently dropped it). The hook fires only after a successful built-in or custom call, with (tool_name, chat_id, result).
• client_adapter.py: keeps the active RoomTurnEmitter per room and passes a hook that calls mark_reply_settled() when settles_turn_reply(tool_name) — the canonical name is known in-process regardless of what the ACP title says.
• room_emitter.py: __aexit__ relays held text only if neither the in-process mark nor the stream-based detection settled the reply. The stream path stays for remote band-mcp servers the SDK never executes.

Tests

tests/integrations/acp/test_client_adapter_behavior.py drives the real local MCP server through the fake ACP agent with a title that differs from the tool name (will_call_mcp_tool(..., title=)):

• intent-titled band_no_reply → closing text not relayed (red before: ["Huginn's me…ed the turn."] == [])
• intent-titled band_send_message → posts once, no text duplicate (red before)
• intent-titled observing tool (band_get_participants) → text still relayed

tests/mcp/test_engine.py: hook observes successful built-in and custom calls with the room id; skipped when the call fails.

pytest tests/mcp/test_engine.py tests/integrations/acp tests/integrations/test_mcp_backends.py tests/integrations/mcp: 476 passed, 10 skipped. pre-commit (ruff, pyrefly, secrets) clean.

Not in this PR

_resolve_mcp_tool_name still rejects mcp__band_<tool>; irrelevant once execution-time settlement exists, and the narrated tool_call event names on OMP remain the model's intent phrase (cosmetic).

Testing

• Unit tests pass (uv run pytest tests/ --ignore=tests/integration/): 6289 passed, 658 skipped
• Pre-commit checks pass (ruff check/format, pyrefly, secrets) on the changed files
• Integration tests: not run (no live ACP harness in this environment); the behavior tests above exercise the real local MCP server over a real ACP wire against a fake agent

Checklist

• PR title follows Conventional Commits format
• Code follows project style guidelines
• Tests added/updated as needed
• Documentation updated as needed (docstrings on turn_replied_in_room, mark_reply_settled, ToolResultHook; changelog is release-please generated from the commit)