feat: add browser-safe js file util shims [WPB-23964]

[Garzas]

https://wearezeta.atlassian.net/browse/WPB-23964

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• The PR Title

  • conforms to the style of semantic commits messages¹ supported in Wire's Github Workflow²
  • contains a reference JIRA issue number like SQPIT-764
  • answers the question: If merged, this PR will: ... ³

• The PR Description

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What's new in this PR?

Issues

• Some JS runtime helpers still assumed native filesystem behavior.
• On web, this could lead to unsupported file operations and incorrect persistent-storage cleanup.
• JS tests also needed an IndexedDB bootstrap in the Node-based test environment.

Causes (Optional)

• Native targets use file-based storage, while web uses browser-managed storage like IndexedDB.
• The existing JS helpers were either unimplemented or too close to native filesystem semantics.
• The shared FileUtil API had no web-specific persistent cleanup path.

Solutions

• Added deletePersistentDirectory(...) to the shared FileUtil API.
• Implemented the JS version using IndexedDB cleanup.
• Mapped the new API to existing directory deletion on native targets.
• Replaced unsupported web filesystem helpers in CoreCrypto with safe inert shims.
• Added a one-time warning log for unexpected JS filesystem shim usage.
• Added an IndexedDB bootstrap for JS tests.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Test Results

0 tests   - 4 718   0 ✅  - 4 601   0s ⏱️ - 2m 45s
0 suites  -   779   0 💤  -   117 
0 files    -   779   0 ❌ ±    0 

Results for commit cbeb734. ± Comparison against base commit 55fa770.

♻️ This comment has been updated with latest results.

[github-actions]

Bencher Report

Branch	kubaz/feat/js-runtime-fileshim
Testbed	ubuntu-latest

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Benchmark	Latency	microseconds (µs)
com.wire.kalium.benchmarks.logic.CoreLogicBenchmark.createObjectInFiles	📈 view plot ⚠️ NO THRESHOLD	891.97 µs
com.wire.kalium.benchmarks.logic.CoreLogicBenchmark.createObjectInMemory	📈 view plot ⚠️ NO THRESHOLD	340,636.54 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.inboxPagingDeepPageBenchmark	📈 view plot ⚠️ NO THRESHOLD	132,791.12 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.inboxPagingFirstPageBenchmark	📈 view plot ⚠️ NO THRESHOLD	126,700.44 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.localMarkAsReadBenchmark	📈 view plot ⚠️ NO THRESHOLD	3,836.42 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.messagePagingDeepPageBenchmark	📈 view plot ⚠️ NO THRESHOLD	26,984.96 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.messagePagingFirstPageBenchmark	📈 view plot ⚠️ NO THRESHOLD	11,428.69 µs
com.wire.kalium.benchmarks.persistence.MessagesNoPragmaTuneBenchmark.messageInsertionBenchmark	📈 view plot ⚠️ NO THRESHOLD	1,375,111.68 µs
com.wire.kalium.benchmarks.persistence.MessagesNoPragmaTuneBenchmark.queryMessagesBenchmark	📈 view plot ⚠️ NO THRESHOLD	21,606.23 µs

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