Clean up codebase and fix server host binding for IPv6 support

Cleanup:
- Remove unused aircraft-icon.svg (replaced by type-specific icons)
- Remove test files: beast-dump-with-heli.bin, beast.test, main, old.json, ux.png
- Remove duplicate config.json.example (kept config.example.json)
- Remove empty internal/coverage/ directory
- Move CLAUDE.md to project root
- Update assets.go documentation to reflect current icon structure
- Format all Go code with gofmt

Server Host Binding Fix:
- Fix critical bug where server host configuration was ignored
- Add host parameter to Server struct and NewWebServer constructor
- Rename NewServer to NewWebServer for better clarity
- Fix IPv6 address formatting in server binding (wrap in brackets)
- Update startup message to show correct bind address format
- Support localhost-only, IPv4, IPv6, and interface-specific binding

This resolves the "too many colons in address" error for IPv6 hosts like ::1
and enables proper localhost-only deployment as configured.

Closes #15

🤖 Generated with [Claude Code](https://claude.ai/code)

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

internal/icao/database.go

@@ -30,7 +30,7 @@ type CountryInfo struct {
 // NewDatabase creates a new ICAO database with comprehensive allocation data
 func NewDatabase() (*Database, error) {
 	allocations := getICAOAllocations()
-	
+
 	// Sort allocations by start address for efficient binary search
 	sort.Slice(allocations, func(i, j int) bool {
 		return allocations[i].StartAddr < allocations[j].StartAddr
@@ -265,4 +265,4 @@ func (d *Database) LookupCountry(icaoHex string) (*CountryInfo, error) {
 // Close is a no-op since we don't have any resources to clean up
 func (d *Database) Close() error {
 	return nil
-}
+}