Fix BEGIN leaking into SQL panel when using DatabaseCache store

[marcosalvesdev]

Description

Fixes #2338

When using CacheStore with Django's DatabaseCache backend, the transaction.atomic() calls used internally by the toolbar to persist its own data were emitting BEGIN/COMMIT (or SAVEPOINT/RELEASE SAVEPOINT inside a
test transaction) into the SQL panel. These commands carry no table name, so the existing
SKIP_TOOLBAR_QUERIES filter — which works by matching known toolbar table names in the SQL string — could
never suppress them.

The fix introduces a ContextVar (sql_recording, default True) in tracking.py and a context manager
no_sql_recording() that sets it to False for the duration of the toolbar's own persistence operations. The
decision logic in NormalCursorMixin._record() now consults this flag: when sql_recording=False, only
queries that explicitly reference a known toolbar table (and where SKIP_TOOLBAR_QUERIES=False) are recorded — preserving the existing opt-in behavior while suppressing table-less control commands unconditionally.

no_sql_recording() is applied in two places:

• _UntrackedCache.untracked() — covers all cache operations made by CacheStore
• DatabaseStore.set() and DatabaseStore.save_panel() — covers the transaction.atomic() calls made directly
  by DatabaseStore

Checklist:

• I have added the relevant tests for this change.
• I have added an item to the Pending section of docs/changes.rst.

AI/LLM Usage

• This PR includes code generated with the help of an AI/LLM

[marcosalvesdev]

👋🏼 Hey you!

Guys, the tox tests for SQLite are failing. I investigated it and found that the behavior expected in tests/panels/test_sql.py, which assumed that boolean parameters for non-PostgreSQL databases would be introduced in Django 6.2, was already introduced in 6.1. So I opened issue #2398. I was thinking about fixing it in this PR, but I would like to hear your thoughts first to make sure my findings are correct and the fix suggested in the issue is the right one.

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
debug_toolbar
store.py
debug_toolbar/panels/sql
tracking.py					273-274
Project Total

This report was generated by python-coverage-comment-action

[marcosalvesdev]

👋🏼 Hey you!

Guys, the tox tests for SQLite are failing. I investigated it and found that the behavior expected in tests/panels/test_sql.py, which assumed that boolean parameters for non-PostgreSQL databases would be introduced in Django 6.2, was already introduced in 6.1. So I opened issue #2398. I was thinking about fixing it in this PR, but I would like to hear your thoughts first to make sure my findings are correct and the fix suggested in the issue is the right one.

Fixed by #2403. Thanks @matthiask 👍🏼