[thekevinbot]

Fixes #1616

A query that skips its own read of the disk (the TypeScript binding's queries, or any core caller with fresh reads off) took only the DB mutex, which a watch batch releases between statements while its transaction is open. The query then ran inside that transaction and could see one table updated and another not, or rows a foreign-key failure later rolled back. Fix: every query holds the index-still lock that watch batches and reconciles take, whether or not it reads the disk first (DirSQL::refresh in packages/rust/src/lib.rs).

The CLI server's queries already wait on that lock since #1577 (they reconcile first), so the issue's server repros pass on main; watch_batch_isolation_e2e.rs keeps them as a regression guard. The red proof is watch_batch_isolation.rs, which queries mid-batch with fresh reads off.

Red run (test commit 67c2a59): https://github.com/thekevinscott/dirsql/actions/runs/41916391931 -- Integration tests and Windows tests fail on exactly the new assertions: torn read: [{"na": Integer(2), "nb": Integer(1)}] and read rows the batch rolled back ([c1] vs [c1, orphan]).

Hand check with the release binary: the issue's torn repro answers {"na":2,"nb":2} 25/25; the dirty repro never returns c2 (the query reports the foreign-key violation instead, from its own read of the disk).

E2E Verification

• Ran e2e suites locally for every affected SDK
• Python SDK e2e: pass
• TypeScript SDK e2e: pass
• Rust core e2e (if applicable): pass
• packages/python/e2e-attestations/<branch>.json receipt written if packages/python changed (just e2e-attest-python)
• packages/ts/e2e-attestations/<branch>.json receipt written if packages/ts changed (just e2e-attest-ts)
• Command(s) run:
  • cargo test -p dirsql --features cli --tests --no-fail-fast (all pass)
  • python: testing-conventions e2e attest 'uv run python -m pytest tests/e2e/fresh_declared_repros_test.py tests/e2e/query_contract_test.py tests/e2e/on_file_query_test.py tests/e2e/watch_speed_test.py tests/e2e/server_speed_test.py -x -q'
  • ts: testing-conventions e2e attest 'pnpm exec vitest run --dir tests/e2e fresh-declared-repros query-contract fanout'
• Result summary: Python 20 passed; TS 17 passed; Rust suite green.

Changelog / Migrations

• Changelog fragment added under <root>/<pkg>/changelog.d/ for each changed package (or: skip-changelog trailer on a commit with reason)
• Migration fragment with the same slug added under <root>/<pkg>/migrations.d/ for each changed package (every subsection but Summary _None._ when nothing breaks)