feat(mesh): config-driven regions with stale purge and coverage fix

- Extended RegionAnchor with local_name, description, aliases, cities
- Moved region geographic context from hardcoded Python to config.yaml
- Added 7-day stale node purge in _do_refresh (556 → 267 nodes)
- Fixed coverage lookup: str(node_num) → node_num (int key)
- Added bidirectional neighbor lookup for better region assignment
- Dynamic geography building in router from config
- Reporter reads region context from config instead of hardcoded dict

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

meshai/main.py

@@ -250,7 +250,8 @@ class MeshAI:
         # Mesh reporter (for LLM prompt injection and commands)
         if self.health_engine and self.data_store:
             from .mesh_reporter import MeshReporter
-            self.mesh_reporter = MeshReporter(self.health_engine, self.data_store)
+            mi_regions = self.config.mesh_intelligence.regions if self.config.mesh_intelligence else []
+            self.mesh_reporter = MeshReporter(self.health_engine, self.data_store, region_configs=mi_regions)
             logger.info("Mesh reporter enabled")
         else:
             self.mesh_reporter = None