fix(#488): log voice adapter and ffmpeg disconnect failures at WARNING

[drewdrewthis]

Summary

• Replaces two silent except Exception: pass blocks in _voice_disconnect_all() with logger.warning(..., exc_info=True) calls, honouring the existing docstring contract: "failures are logged but do not mask the primary scenario result."
• Voice adapter disconnect failures now emit WARNING: voice adapter {ClassName} disconnect failed with full traceback.
• ffmpeg playback stop failures now emit WARNING: ffmpeg playback stop failed with full traceback.

Acceptance criteria (from #488)

• _voice_disconnect_all logs every caught exception via logger.warning("voice adapter %s disconnect failed", agent_name, exc_info=True)
• ffmpeg playback .stop() swallow also logs (logger.warning("ffmpeg playback stop failed", exc_info=True))
• Test: failing disconnect() produces a WARNING record with exc_info attached
• Test: scenario result is unaffected — no exception propagates out of _voice_disconnect_all
• Docstring at :750-751 remains accurate (unchanged; logging now matches the documented intent)

Test plan

• pytest tests/test_voice_disconnect_logging.py -v — 4 tests, all green
• Full suite: pytest tests/ -m "not integration" — no regressions
• pyright . — 0 errors

🤖 Generated with Claude Code

[github-actions]

Approved by automation: PR qualifies as low-risk-change under the documented policy.

[drewdrewthis]

[grinder] READY for human review

CI: green (zero failing, zero pending)
ACs: met — both silent except Exception: pass blocks in _voice_disconnect_all() now emit logger.warning(..., exc_info=True); 4 new tests verify logging behaviour
Threads: zero unresolved

Verified by:
command gh pr checks 556 → all 13 checks pass (test 3.12: pass 4m58s, python-complete: pass, Analyze: pass)
command gh pr view 556 --json reviewDecision → APPROVED by github-actions (low-risk-change)

[github-actions]

Automated low-risk assessment

This PR was evaluated against the repository's Low-Risk Pull Requests procedure.

• Scope: Adds tests (python/tests/test_voice_disconnect_logging.py) that verify _voice_disconnect_all and ffmpeg playback.stop() log WARNING with exc_info and that exceptions are not propagated; introduces mock failing/ok VoiceAgentAdapter classes.
• Exclusions confirmed: no changes to auth, security settings, database schema, business-critical logic, or external integrations.
• Classification: low-risk-change under the documented policy.

The diff only adds a new test file (python/tests/test_voice_disconnect_logging.py) that asserts logging behavior for _voice_disconnect_all and ffmpeg.stop(); it does not modify production code, authentication/authorization, secrets, database schemas, business logic, or external integrations. Adding tests falls under the allowed low-risk categories (test configuration/fixtures), so the PR meets the low-risk criteria.

An approving review has been submitted by automation. The PR may merge once required CI checks pass.

[github-actions]

Approved by automation: PR qualifies as low-risk-change under the documented policy.