feat: add automatic cluster sync and IPAM discovery with configurable intervals, firewall log file parsing, and enhanced flow prioritization

Add RuntimeSettingsRead/RuntimeSettingsUpdate schemas with auto_node_sync_enabled/auto_node_sync_interval_minutes/auto_ipam_sync_enabled/auto_ipam_sync_interval_minutes/last_node_auto_sync_at/last_ipam_auto_sync_at fields, implement firewall_log_lines_from_files to parse /var/log/pve-firewall.log with max_lines limit and error collection, extend collect_firewall_log

backend/tests/test_agent_firewall_logs.py

@@ -0,0 +1,30 @@
+import importlib.util
+from pathlib import Path
+
+
+def load_agent_module():
+    path = Path(__file__).resolve().parents[1] / "app" / "agent_assets" / "nexafabric-agent.py"
+    spec = importlib.util.spec_from_file_location("nexafabric_agent", path)
+    assert spec and spec.loader
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_parse_proxmox_reject_firewall_log_line():
+    agent = load_agent_module()
+    line = (
+        "100 6 tap100i0-IN 09/Jul/2026:23:04:58 +0200 REJECT: IN=fwbr100i0 OUT=fwbr100i0 "
+        "PHYSIN=fwln100i0 PHYSOUT=tap100i0 SRC=172.16.155.74 DST=172.16.0.100 LEN=52 "
+        "TTL=128 ID=47107 PROTO=TCP SPT=58945 DPT=80"
+    )
+
+    flow = agent.parse_firewall_log_line(line)
+
+    assert flow["source_ip"] == "172.16.155.74"
+    assert flow["destination_ip"] == "172.16.0.100"
+    assert flow["protocol"] == "tcp"
+    assert flow["source_port"] == 58945
+    assert flow["destination_port"] == 80
+    assert flow["decision"] == "blocked"
+    assert flow["state"] == "blocked"