fix: bypass cache for locking document reads

[abnegate]

Summary

• bypass document cache reads when getDocument() is called with forUpdate=true
• avoid saving forUpdate read results back into the normal document cache
• add a regression test that proves stale cached data is ignored for locking reads

Tests

• php vendor/bin/phpunit tests/unit/ForUpdateCacheTest.php
• composer check
• composer lint
• git diff --check

Summary by CodeRabbit

• Bug Fixes

  • Locking reads bypass cache to avoid repopulating stale/partial entries.
  • Update handling refined: timestamp-only/numeric-drift no-ops won’t trigger storage writes; metadata-only changes require update permission. Read-only callers may be downgraded to silent no-ops (no storage write or update event) when stale-cache tolerance applies.
  • Nulling both created/updated timestamps is a no-op (timestamps preserved).

• Tests

  • Added unit and e2e tests covering cache bypass, no-op/timestamp behavior, float equality, and authorization edge cases.