Fix resource leak paths in wallet and cache

[callebtc]

Summary

• ensure Cashu wallet/database handles always close via closeResources helper
• guard ItemManager image import streams with use{} and early returns
• wrap MintIconCache http calls with use to auto close response/streams

Testing

• ./gradlew lintDebug testDebugUnitTest (fails locally: Android SDK not configured in CI env)

[callebtc]

utACK

[callebtc]

Review Summary

Thanks for tightening up the resource handling. The new closeResources() helper in CashuWalletManager and the scoped use { ... } blocks in MintIconCache are good steps toward eliminating leaks.

However, the change in ItemManager.saveItemImage() introduces a regression. By wrapping the InputStream in use { ... } and then falling through the method, the function now always returns false, even when the image was saved successfully. Previously the method returned true from inside the if (inputStream != null) block. We need to keep returning true on success (and only false when no stream is available or an exception is thrown); otherwise callers will treat every save as a failure.

Once that’s addressed, the PR should be in good shape.

Scores (0–10)

• Effectiveness: 4 (regression outweighs the leak fixes)
• Code Style: 8 (clean, consistent Kotlin idioms)
• Safety & Robustness: 3 (always returning false breaks callers)