[mob][locker] Fix Locker file opening and offline cache cleanup

[AmanRajSinghMourya]

Description

Locker was mixing stale file paths with Locker file identity, causing wrong/stale opens, fragile offline behavior, and unsafe cache cleanup.

Fix: Make file opening ID-first, hand off fresh external-open copies, scope cleanup to Locker-owned files, and harden logout/user-details refresh races.
This PR fixes Locker file opening by treating uploadedFileID as the source of truth instead of stale localPath metadata.

Changes included:

• Ignore stale localPath for synced Locker file opens.
• Require uploadedFileID for synced-file open flow.
• Create fresh open_handoff/fileId/timestamp/name copies before opening files externally.
• Preserve visible filenames/extensions using Locker metadata.
• Fail closed instead of handing external apps internal cache/decrypted source paths.
• Keep offline encrypted blobs safe when offline open/decrypt fails.
• Scope cleanup to:
  • offline encrypted blobs
  • ID-keyed cached encrypted/decrypted files
  • open_handoff
  • Clear Locker-owned offline/cache/handoff files before logout teardown.

Tests

• Add tests for file opening, handoff behavior, offline storage cleanup, and cache identity.