🛡️ Sentinel: Fix decompression bomb risk and input/output path collision

[kassoulet]

This PR addresses two security and stability issues:

1. Decompression Bomb Protection: A malicious bzip2 block could theoretically expand to a huge size. We now limit each block to 2MB of uncompressed data.
2. File Overwrite Protection: Since the application uses memory-mapping for the input file, truncating that same file for output (if they were the same) would cause a SIGBUS crash. We now verify they are distinct using canonicalized paths.

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PR created automatically by Jules for task 14830086709159860439 started by @kassoulet

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