refactor(certgen): drop dead native logging code

Remove orphaned native logging that nothing reached:

- The /sdcard/Download zip dump (NativeCertGen.dump and the dumpLogs
  JNI, dump_logs_inner, dump.rs, pub mod dump), superseded by the
  diag.sh export.
- The verbose-marker helpers (sysfs.rs, pub mod sysfs); the manual
  .verbose toggle still works via mod.rs::init's inline check.

Drop the now-unused direct deps zip and libc and the orphaned jstring
import. cargo ndk build is warning-clean.

app/src/main/java/org/matrix/TEESimulator/pki/NativeCertGen.kt

@@ -84,10 +84,6 @@ object NativeCertGen {
 
     private external fun initLogging(verbose: Boolean, logDir: String): Boolean
 
-    private external fun dumpLogs(): String?
-
-    fun dump(): String? = if (isAvailable) dumpLogs() else null
-
     fun parseNativeResult(bytes: ByteArray): Pair<KeyPair, List<Certificate>> {
         val buf = ByteBuffer.wrap(bytes).order(ByteOrder.BIG_ENDIAN)