Fix credential_db schema conflict and add resilience

credential_sniffer and credential_db both wrote to the same credentials.db
with different schemas; credential_db's executescript failed when creating
the crack_status index on an existing table that lacked that column.

Fix: split credential_db's schema init into table DDL + migration + indexes
so missing columns are added before index creation runs. Migration also
handles any future schema drift.

state.py: add 30s timeout + busy_timeout PRAGMA to write connection so
concurrent subprocess writes stop failing with 'database is locked'.

capture_bus.py: reconnect on ENETDOWN instead of aborting the capture
loop — mac_manager temporarily brings the interface down during MAC
rotation which was silently killing all packet capture.

core/state.py

@@ -139,9 +139,10 @@ class StateManager:
 
     def _get_write_conn(self) -> sqlite3.Connection:
         if self._write_conn is None:
-            self._write_conn = sqlite3.connect(self._db_path, check_same_thread=False)
+            self._write_conn = sqlite3.connect(self._db_path, check_same_thread=False, timeout=30)
             self._write_conn.execute("PRAGMA journal_mode=WAL")
             self._write_conn.execute("PRAGMA synchronous=NORMAL")
+            self._write_conn.execute("PRAGMA busy_timeout=30000")
         return self._write_conn
 
     # ------------------------------------------------------------------