fix: logging verbosity now actually applies + per-service log levels

Root causes fixed:
- Dead LOG_LEVEL globals() lookup pinned root logger at INFO regardless of
  PIC_LOG_LEVEL env or config; replaced with _resolve_root_log_level() +
  apply_root_log_level() which sets both root logger and all attached handlers
  at startup and on runtime re-apply.
- set_service_level() only set the named 'pic.<service>' logger; bare module
  loggers (e.g. 'caddy_manager') were never reached, so per-service log files
  stayed 0 bytes. Fixed via _SERVICE_MODULE_LOGGERS map covering all managers.
- Log viewer GET /api/logs had no level filter; added ?level= query param.
- Per-service log levels lived in an out-of-band config/api/log_levels.json
  side-file with no validation; migrated into ConfigManager under a new
  'logging' section ({python:{root,services}, containers:{caddy,coredns,
  wireguard,mailserver,api}}) with get/set helpers, invalid-level rejection,
  and one-time migration from the old file on first load.

New capabilities:
- Container log levels: Caddy (injects global log { level X } + hot reload),
  CoreDNS (DEBUG enables log plugin, else errors-only), WireGuard/mailserver
  via pending_restart path.
- PUT /api/logs/verbosity accepts {python, containers} dict; returns per-entry
  applied:hot|pending_restart status.
- Webui Logs page gains two-section Verbosity tab (Python services + Container
  services) with needs-restart badges.
- managers.py wires per-service loggers before manager instantiation and
  re-applies persisted levels from ConfigManager; legacy log_levels.json read
  removed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_log_manager_extra.py

@@ -356,6 +356,23 @@ class TestSetServiceLevel(unittest.TestCase):
         self.assertIsInstance(levels, dict)
         self.assertIn('svc', levels)
 
+    def test_set_level_also_sets_bare_module_logger(self):
+        """A verbosity change for 'network' must reach BOTH picell.network and
+        the network_manager module logger so per-service files capture every
+        record (the core bug)."""
+        import logging
+        self.lm.add_service_logger('network', {'level': 'INFO'})
+        self.lm.set_service_level('network', 'DEBUG')
+        self.assertEqual(self.lm.service_loggers['network'].level, logging.DEBUG)
+        self.assertEqual(logging.getLogger('network_manager').level, logging.DEBUG)
+
+    def test_set_level_for_routing_covers_firewall_module_logger(self):
+        import logging
+        self.lm.add_service_logger('routing', {'level': 'INFO'})
+        self.lm.set_service_level('routing', 'DEBUG')
+        self.assertEqual(logging.getLogger('routing_manager').level, logging.DEBUG)
+        self.assertEqual(logging.getLogger('firewall_manager').level, logging.DEBUG)
+
 
 class TestGetAllLogFileInfos(unittest.TestCase):
     def setUp(self):