fix: clean observation dogfood telemetry

[cafitac]

Summary

• stop storing/emitting query previews for retrieval observations; keep hash/ref/status telemetry only
• skip deterministic hermes hooks doctor/test pre-LLM payloads as dogfood observations while still exercising context injection
• add observation audit data-quality warnings for low observation counts and high empty-retrieval ratios
• lazily migrate memory_status_transitions on existing DB status update/history paths
• add tests proving Hermes hook context can include retrieved memory content and that actual local Hermes can use injected memory

Verification

• RED confirmed for query preview output, synthetic doctor observation pollution, missing audit quality warnings, and existing DB memory_status_transitions gap
• uv run pytest tests/test_cli.py::test_python_module_cli_approve_fact_migrates_existing_database_without_status_transition_table tests/test_cli.py::test_python_module_cli_retrieve_observe_records_secret_safe_local_observation tests/test_cli.py::test_python_module_cli_observations_audit_reports_frequent_and_stale_refs_without_raw_queries tests/test_cli.py::test_python_module_cli_observations_audit_reports_low_signal_empty_retrievals tests/test_cli.py::test_python_module_cli_observations_list_migrates_existing_database_without_observation_table tests/test_cli.py::test_python_module_cli_hermes_pre_llm_hook_outputs_context_for_hermes_shell_hook_payload tests/test_cli.py::test_python_module_cli_hermes_pre_llm_hook_skips_synthetic_doctor_observation tests/test_cli.py::test_python_module_cli_hermes_pre_llm_hook_injects_retrieved_memory_context -q
• uv run pytest tests/ -q -> 173 passed
• uv run python scripts/check_release_metadata.py
• uv run python scripts/smoke_release_readiness.py
• npm pack --dry-run
• git diff --check
• node --check bin/agent-memory.js
• temp DB dogfood quality smoke: query_preview=None, no raw secret-like query text, audit warnings reported
• static diff secret scan: finding_count: 0

Live Hermes QA

• Created a temporary approved local fact with marker AM_LIVE_E2E_1777567838 scoped to /Users/reddit/Project/agent-memory
• Direct hook output contained <agent_memory_context>, Retrieved fact, and the marker
• Actual Hermes command hermes --accept-hooks -z "What is the Hermes live E2E QA marker? Return only the marker and nothing else." answered with the marker
• Cleanup: deprecated the temporary test fact; review explain showed it is hidden from default retrieval
• Live QA uncovered the existing DB memory_status_transitions migration gap fixed in this PR