fix(core): handle legacy pgvector storage status

[phernandez]

Why

Production Logfire issue #2173 shows project-info requests failing with asyncpg UndefinedColumnError because a legacy search_vector_embeddings table predates the source_hash column used by current count queries.

The physical table can exist before PgVectorIndex.initialize() has run its existing schema repair. Project status currently treats table existence as schema readiness and executes the invalid join, turning a recoverable reindex state into a customer-visible HTTP 500.

Closes #1195.

What Changed

• inspect the Postgres pgvector embeddings columns before running physical count queries
• treat storage without source_hash as outdated and return the existing reindex recommendation contract
• add a Postgres regression that creates the production-shaped legacy table and proves status does not query the missing column

Implementation Details

ProjectService.get_embedding_status() now distinguishes physical-table existence from schema readiness for the built-in pgvector adapter. When the legacy table is detected, it returns vector_tables_exist=False with Vector storage schema is outdated — run: bm reindex --embeddings.

The status path remains read-only. It does not drop, migrate, or rebuild the table; PgVectorIndex.initialize() remains the single repair owner and will recreate the incompatible physical table when indexing runs. External adapters remain manifest-only, and SQLite behavior is unchanged.

Testing

Automated

• LOGFIRE_IGNORE_NO_CONFIG=1 uv run pytest -p pytest_mock --no-cov -q tests/services/test_project_service_embedding_status.py: 15 passed, 1 skipped
• BASIC_MEMORY_TEST_POSTGRES=1 LOGFIRE_IGNORE_NO_CONFIG=1 uv run pytest -p pytest_mock --no-cov -q tests/services/test_project_service_embedding_status.py: 14 passed, 2 skipped
• just fast-check: passed after installing configured optional dependencies with uv sync --all-extras
• git diff --check: passed

Manual

• Inspected the production trace and verified the failing SQL joins on the legacy missing column before any pgvector initialization repair runs.

Risks / Follow-ups

• This change only converts legacy physical storage into an explicit reindex status; it does not perform repair from the read endpoint.
• After this Core PR merges, Basic Memory Cloud must pin the resulting Core commit, deploy it, and observe a non-recurrence window before Logfire #2173 can be closed.

[chatgpt-codex-connector]

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