logging: make the writer total and harden export

Never let a log-write or export failure reach the uncaught handler: wrap the async writer and crash path, synchronize export with rotation, and tolerate vanished files. Redact the Logcat stack-trace copy, stop leaking rows=0 on writes, shut down the previous writer on re-init, and drop unused API. Strengthen tests for the batched write path, rotation count and throwable redaction.

app/src/main/kotlin/com/subtracks/data/db/DbLogging.kt

@@ -6,6 +6,7 @@ import androidx.sqlite.SQLiteConnection
 import androidx.sqlite.SQLiteDriver
 import androidx.sqlite.SQLiteStatement
 import com.subtracks.log.Log
+import kotlinx.coroutines.CancellationException
 
 data class SqlExecution(
     val sql: String,
@@ -102,6 +103,8 @@ class LoggedMigration(
         val start = System.nanoTime()
         try {
             delegate.migrate(connection)
+        } catch (cancellation: CancellationException) {
+            throw cancellation
         } catch (failure: Throwable) {
             Log.e("sql", "migration $label failed after ${(System.nanoTime() - start) / 1_000_000}ms", failure)
             throw failure