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/merger/merger.go

@@ -111,7 +111,7 @@ func (a *AircraftState) MarshalJSON() ([]byte, error) {
 		SelectedAltitude int     `json:"SelectedAltitude"`
 		SelectedHeading  float64 `json:"SelectedHeading"`
 		BaroSetting      float64 `json:"BaroSetting"`
-		
+
 		// From AircraftState
 		Sources         map[string]*SourceData `json:"sources"`
 		LastUpdate      time.Time              `json:"last_update"`
@@ -155,7 +155,7 @@ func (a *AircraftState) MarshalJSON() ([]byte, error) {
 		SelectedAltitude: a.Aircraft.SelectedAltitude,
 		SelectedHeading:  a.Aircraft.SelectedHeading,
 		BaroSetting:      a.Aircraft.BaroSetting,
-		
+
 		// Copy all fields from AircraftState
 		Sources:         a.Sources,
 		LastUpdate:      a.LastUpdate,
@@ -238,7 +238,7 @@ type Merger struct {
 	sources       map[string]*Source        // Source ID -> source information
 	icaoDB        *icao.Database            // ICAO country lookup database
 	mu            sync.RWMutex              // Protects all maps and slices
-	historyLimit  int                      // Maximum history points to retain
+	historyLimit  int                       // Maximum history points to retain
 	staleTimeout  time.Duration             // Time before aircraft considered stale (15 seconds)
 	updateMetrics map[uint32]*updateMetric  // ICAO24 -> update rate calculation data
 }
@@ -291,13 +291,13 @@ func (m *Merger) AddSource(source *Source) {
 // UpdateAircraft merges new aircraft data from a source using intelligent fusion strategies.
 //
 // This is the core method of the merger, handling:
-//   1. Aircraft state creation for new aircraft
-//   2. Source data tracking and statistics
-//   3. Multi-source data fusion with conflict resolution
-//   4. Historical data updates with retention limits
-//   5. Distance and bearing calculations
-//   6. Update rate metrics
-//   7. Source status maintenance
+//  1. Aircraft state creation for new aircraft
+//  2. Source data tracking and statistics
+//  3. Multi-source data fusion with conflict resolution
+//  4. Historical data updates with retention limits
+//  5. Distance and bearing calculations
+//  6. Update rate metrics
+//  7. Source status maintenance
 //
 // Data fusion strategies:
 //   - Position: Use source with strongest signal
@@ -326,7 +326,7 @@ func (m *Merger) UpdateAircraft(sourceID string, aircraft *modes.Aircraft, signa
 			AltitudeHistory: make([]AltitudePoint, 0),
 			SpeedHistory:    make([]SpeedPoint, 0),
 		}
-		
+
 		// Lookup country information for new aircraft
 		icaoHex := fmt.Sprintf("%06X", aircraft.ICAO24)
 		if countryInfo, err := m.icaoDB.LookupCountry(icaoHex); err == nil {
@@ -339,7 +339,7 @@ func (m *Merger) UpdateAircraft(sourceID string, aircraft *modes.Aircraft, signa
 			state.CountryCode = "XX"
 			state.Flag = "🏳️"
 		}
-		
+
 		m.aircraft[aircraft.ICAO24] = state
 		m.updateMetrics[aircraft.ICAO24] = &updateMetric{
 			updates: make([]time.Time, 0),
@@ -585,10 +585,10 @@ func (m *Merger) updateHistories(state *AircraftState, aircraft *modes.Aircraft,
 // updateUpdateRate calculates and maintains the message update rate for an aircraft.
 //
 // The calculation:
-//   1. Records the timestamp of each update
-//   2. Maintains a sliding 30-second window of updates
-//   3. Calculates updates per second over this window
-//   4. Updates the aircraft's UpdateRate field
+//  1. Records the timestamp of each update
+//  2. Maintains a sliding 30-second window of updates
+//  3. Calculates updates per second over this window
+//  4. Updates the aircraft's UpdateRate field
 //
 // This provides real-time feedback on data quality and can help identify
 // aircraft that are updating frequently (close, good signal) vs infrequently
@@ -644,10 +644,10 @@ func (m *Merger) getBestSignalSource(state *AircraftState) string {
 // GetAircraft returns a snapshot of all current aircraft states.
 //
 // This method:
-//   1. Filters out stale aircraft (older than staleTimeout)
-//   2. Calculates current age for each aircraft
-//   3. Determines closest receiver distance and bearing
-//   4. Returns copies to prevent external modification
+//  1. Filters out stale aircraft (older than staleTimeout)
+//  2. Calculates current age for each aircraft
+//  3. Determines closest receiver distance and bearing
+//  4. Returns copies to prevent external modification
 //
 // The returned map uses ICAO24 addresses as keys and can be safely
 // used by multiple goroutines without affecting the internal state.
@@ -813,7 +813,7 @@ func calculateDistanceBearing(lat1, lon1, lat2, lon2 float64) (float64, float64)
 func (m *Merger) Close() error {
 	m.mu.Lock()
 	defer m.mu.Unlock()
-	
+
 	if m.icaoDB != nil {
 		return m.icaoDB.Close()
 	}