feat(firewall): persist firewall snapshots to SQLite (F001/D007)

save_state_report now also writes the address-list + firewall-rule snapshot into
the app.db firewall_snapshots tables, making the audit trail independent of git.
Removes the 'git-visible data/mikrotik' framing.

app/firewall.py

@@ -143,9 +143,11 @@ class MikrotikFirewall:
         """Save current address lists and firewall rules for auditing.
 
         Writes structured snapshots to ``<report_dir>/mikrotik/data/`` and to
-        the common ``data/mikrotik/`` directory (overwritten every run so git
+        the common ``data/mikrotik/`` directory (scratch mirror for debugging;
-        can diff changes to the firewall state over time), plus a timestamped
+        **not** a git audit trail), plus a timestamped JSON report under
-        JSON report under ``<report_dir>/mikrotik/``.
+        ``<report_dir>/mikrotik/``. The authoritative long-term audit trail is
+        the SQLite ``firewall_snapshots`` tables (see ``app.db``), which are
+        appended here regardless of the file writes.
         """
         state = {
             "router": self.router_ip,
@@ -174,11 +176,31 @@ class MikrotikFirewall:
                     os.path.join(data_dir, f"firewall_{version}.json"),
                     state["firewall_rules"][version])
 
+        # Persist a SQLite snapshot (authoritative audit trail, independent of
+        # git). Best-effort: never breaks a router sync if the DB is down.
+        self._persist_snapshot_to_db(state)
+
         timestamp = datetime.now().strftime("%Y-%m-%d-%H-%M-%S")
         report_path = os.path.join(report_dir, "mikrotik", f"{timestamp}.json")
         self._write_json(report_path, state)
         return report_path
 
+    @staticmethod
+    def _persist_snapshot_to_db(state: dict) -> None:
+        """Write the firewall snapshot into the SQLite store (best-effort)."""
+        try:
+            from .db import get_connection
+            from .db import repositories as repo
+            repo.save_firewall_snapshot(
+                get_connection(),
+                address_lists_v4=state["address_lists"]["ipv4"],
+                address_lists_v6=state["address_lists"]["ipv6"],
+                rules_v4=state["firewall_rules"]["ipv4"],
+                rules_v6=state["firewall_rules"]["ipv6"],
+            )
+        except Exception as exc:
+            print(f"WARN: could not persist firewall snapshot to db ({exc})")
+
     def sync_blocklist(self, blocked_ipv4: Iterable[str],
                        blocked_ipv6: Iterable[str],
                        dry_run: bool = False,
@@ -186,10 +208,12 @@ class MikrotikFirewall:
         """Synchronize the Blocked list cumulatively and audit the result.
 
         The blocklist is grow-only: targets are added when present in the
-        complete set (all git history of the blocklist files + the current
+        complete cumulative set (git history of the blocklist files + the
-        working files + this scan's targets) and never removed automatically.
+        current working files + this scan's targets) and never removed
-        Only router entries absent from the complete set — i.e. never blocked
+        automatically. Only router entries absent from the complete set — i.e.
-        by the system — are pruned. See ``app.blocklist_history``.
+        never blocked by the system — are pruned. The history now lives in the
+        SQLite blocklist ledger (``app.db`` ``blocklist_entries``); git history
+        remains a read-only fallback. See ``app.blocklist_history``.
         """
 
         desired_ipv4 = set(blocked_ipv4)