Skip slicer processing for unmodified DEX files

Slicer's `CreateFullIr` and `CreateImage` operations are highly CPU-intensive and cause significant load latency for large DEX files. We hence introduce a fast-path optimization using `memmem` to perform a raw binary scan of the DEX buffer for target signatures prior to processing.

If no matching signatures are found, the expensive IR parsing and image rebuilding phases are bypassed entirely, and the original file descriptor is safely returned.

Moreover, we update the logging tag to `VectorDaemon`.