Driver and agent leak file handles when an exception interrupts a stream #10

Contexte

Several file streams in the driver and agent modules are opened and closed by hand instead of with try-with-resources. If anything throws between the open and the .close(), the handle leaks. On Windows a leaked handle keeps the file locked, which then breaks later writes/deletes of the same pack folder (the write-path this fork focuses on).

Description

Wrap every manually closed stream in try-with-resources so the handle is released even when an exception is thrown mid-way. Pure robustness change, no behaviour change on the happy path.

Fichiers concernes

• driver/src/main/java/studio/driver/fs/CipherUtils.java:56-64 (addBootFileV2) — FileInputStream riFis and FileOutputStream btFos closed by hand
• driver/src/main/java/studio/driver/raw/RawStoryTellerAsyncDriver.java:516-518 (dumpSector) — FileOutputStream sectorOutputStream closed after writeByteBufferToStream, which can throw
• agent/src/main/java/studio/agent/UnofficialMetadataAdvice.java:59-62 — FileOutputStream fos around a Base64.decode + write
• driver/src/test/java/studio/driver/fs/CipherUtilsStreamLifecycleTest.java (new) — forces a failure after the stream is opened and asserts the file is not locked / handle released
• Existing patterns to reuse: driver/src/test/java/studio/driver/fs/FilesWalkResourceLeakTest.java, web-ui/src/test/java/studio/webui/service/ConversionStreamLifecycleTest.java

Plan d'implementation

1. CipherUtils.addBootFileV2: try-with-resources on both streams.
2. RawStoryTellerAsyncDriver.dumpSector: try-with-resources on sectorOutputStream.
3. UnofficialMetadataAdvice: try-with-resources on fos.
4. Add a stream-lifecycle test for addBootFileV2 (e.g. truncated/unreadable ri file) that asserts the boot file can be deleted afterwards, which is the observable Windows symptom.
5. mvn -pl driver,agent test green.

Criteres d'acceptation

• No manual .close() left on these three sites; all use try-with-resources
• New test fails on the old code (handle leaked) and passes on the fix
• mvn -pl driver,agent test green on Ubuntu and Windows CI
• git diff --exit-code clean after the build (no tracked file rewritten)

Complexite

S