fix(repair): recognize SQLite 3.53 FTS5 corruption

[igorls]

Summary

• recognize SQLite 3.53.x's fts5: corruption found reading blob ... wording as the same isolated, recoverable FTS5 index corruption already handled by repair
• keep mixed FTS5 plus page/row corruption classified as unsafe to auto-heal
• add regression coverage for the new diagnostic shape

Root cause

PRAGMA quick_check changed the wording it emits for a corrupt FTS5 index on SQLite 3.53.x. MemPalace only matched the older malformed inverted index for FTS5 table text, so repair treated the derived-index failure as broader SQLite corruption and aborted instead of rebuilding the index.

Closes #1925.

Validation

• python -m pytest tests/test_repair.py -q — 90 passed
• ruff check mempalace/repair.py tests/test_repair.py
• ruff format --check mempalace/repair.py tests/test_repair.py
• full non-benchmark suite: 2,988 passed, 268 skipped; 12 unrelated Windows environment failures (WSL Bash cannot resolve the Windows worktree path; Strawberry OpenSSL points at a missing build-time openssl.cnf)

[igorls]

Closing as redundant after rebasing against the current develop release line. Commit f9db9b7, merged via #1928 and now included in develop/#2020, already implements the SQLite 3.53 FTS5 wording fix with broader end-to-end regression coverage. No need to carry a competing patch.