Release the thread lock when IPC acquisition fails

[zhechen-cs]

Description

Release the thread lock when LockLocalStorage cannot acquire its IPC lock. A failed __enter__ never reaches __exit__, so the previous code left the thread lock held after a timeout, acquisition error or interruption, preventing reuse of the same lock object.

Regression coverage verifies cleanup and successful reuse after each failure, while preserving the original exceptions. This is independent of the lock-file cleanup in #2172.

Fixes #2202

Status

Ready for review.

Validation

• Local and base storage tests: 33 passed, 3 subtests passed (Python 3.12).
• All three regression cases fail on unmodified production code because the thread lock stays held.
• Black, isort, flake8, pylint and git diff --check pass for the changed files.
• Live cloud integration tests were not run.

Checklist

• Code linting
• Documentation (no public API change)
• Tests
• ICLA (small bug fix)