Add IndexedDB integration tests for Planet CacheManager.js

[farhan-momin]

Summary

• This PR adds comprehensive integration tests for planet/js/CacheManager.js, covering IndexedDB initialization, all cache operations (metadata, project data, thumbnail), expiry logic, LRU cache removal, cache stats, and cleanup, using in-memory IndexedDB from fake-indexeddb.
• The tests include 6 todos in Jest tests (also shown in results for npm run test).

---

Changes

1. Added fake-indexeddb package for testing IndexedDB operations

• What it is: fake-indexeddb is an in-memory implementation of the IndexedDB API for Node.js environments.
• Why it is needed: Without a real IndexedDB implementation, its operations in CacheManager.js cannot be tested.
• How it is used: The IDBFactory and IDBKeyRange from fake-indexeddb Package are used in the IndexedDB CacheManager integration test suite. This allows to open a in-memory IndexedDB database, and execute all DB operations as they would in a browser.

2. Added 38 IndexedDB integration tests using fake-indexeddb for CacheManager.js

---

Test Additions

Describe Block	Tests Added	Tests
init()	5	returns true on success and sets isInitialized calls clearExpired automatically returns false when indexedDB is missing skips re-opening DB on second call creates all three object stores
cacheMetadata / getMetadata	4	cache and retrieve metadata by id unknown id returns null expired entry returns null non-expired entry returns data
cacheProject / getProject	4	cache and retrieve project by id unknown id returns null expired project returns null project stored past metadataExpiry but within projectExpiry
cacheThumbnail / getThumbnail	5	Cache and retrieve thumbnail data URL cacheThumbnail returns value unknown id returns null expired thumbnail returns null getThumbnail does not update lastAccessed
clearExpired	5	returns 0 when nothing expired removes only expired metadata removes only expired projects clears from all three stores returns 0 after clearAll()
clearAll	4	clearAll returns true getStats return all zeros after clearing cached items are inaccessible after clearing calling twice returns true both times
getStats	5	All zeros after init accurate counts after caching Returns all zeros after clearAll() re-caching same id does not double-count counts expired entries
enforceMaxSize	3	count stays at maxCacheSize after insertion beyond max does not remove when count below the limit LRU removal: oldest lastAccessed entry is removed first on overflow
updateLastAccessed	3	getMetadata updates lastAccessed does not throw for non-existent key getProject updates lastAccessed

Total tests added: 38

---

Steps to Test PR

1. Install dependencies:
   npm install
   (Ensures fake-indexeddb package is added)

2. Run the test suite:
   npm run test

3. All test should pass

---

Coverage

Before

After

---

Verification

All CacheManager.js tests pass

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[farhan-momin]

@omsuneri @walterbender Ready for review

[7se7en72025]

LGTM !! @walterbender