Remove BGP keepalive logging and add peer tracking

- Created bgp_peers table to track all BGP peers
- Added PeerHandler to update peer last seen times for all message types
- Removed verbose BGP keepalive debug logging
- BGP keepalive messages now silently update peer tracking

Refactor HTML templates to use go:embed

- Created internal/templates package with embedded templates
- Moved status.html from inline const to separate file
- Templates are parsed once on startup
- Server now uses parsed template instead of raw string

Optimize AS data embedding with gzip compression

- Changed asinfo package to embed gzipped data (2.4MB vs 12MB)
- Updated Makefile to gzip AS data during update
- Added decompression during initialization
- Raw JSON file excluded from git

.gitignore

@@ -28,4 +28,7 @@ go.work.sum
 *.db-wal
 
 # Temporary files
-*.tmp
+*.tmp
+
+# Raw AS data (we only commit the gzipped version)
+pkg/asinfo/asdata.json