feat(idlewatcher): implement real-time SSE-based loading page with enhanced UX

This major overhaul of the idlewatcher system introduces a modern, real-time loading experience with Server-Sent Events (SSE) streaming and improved error handling.

- **Real-time Event Streaming**: New SSE endpoint (`/$godoxy/wake-events`) provides live updates during container wake process
- **Enhanced Loading Page**: Modern console-style interface with timestamped events and color-coded status messages
- **Improved Static Asset Management**: Dedicated paths for CSS, JS, and favicon to avoid conflicting with upstream assets
- **Event History Buffer**: Stores wake events for reconnecting clients and debugging

- Refactored HTTP request handling with cleaner static asset routing
- Added `WakeEvent` system with structured event types (starting, waking_dep, dep_ready, container_woke, waiting_ready, ready, error)
- Implemented thread-safe event broadcasting using xsync.Map for concurrent SSE connections
- Enhanced error handling with detailed logging and user-friendly error messages
- Simplified loading page template system with better asset path management
- Fixed race conditions in dependency waking and state management

- Removed `common.go` functions (canceled, waitStarted) - moved inline for better context
- Updated Waker interface to accept context parameter in Wake() method
- New static asset paths use `/$godoxy/` prefix to avoid conflicts

- Console-style output with Fira Code font for better readability
- Color-coded event types (yellow for starting, blue for dependencies, green for success, red for errors)
- Automatic page refresh when container becomes ready
- Improved visual design with better glassmorphism effects and responsive layout
- Real-time progress feedback during dependency wake and container startup

This change transforms the static loading page into a dynamic, informative experience that keeps users informed during the wake process while maintaining backward compatibility with existing routing behavior.

internal/watcher/health/monitor/raw.go

@@ -33,13 +33,14 @@ func (mon *RawHealthMonitor) CheckHealth() (types.HealthCheckResult, error) {
 	url := mon.url.Load()
 	start := time.Now()
 	conn, err := mon.dialer.DialContext(ctx, url.Scheme, url.Host)
+	lat := time.Since(start)
 	if err != nil {
 		errMsg := err.Error()
 		if strings.Contains(errMsg, "connection refused") ||
 			strings.Contains(errMsg, "connection reset by peer") ||
 			strings.Contains(errMsg, "connection closed") {
 			return types.HealthCheckResult{
-				Latency: time.Since(start),
+				Latency: lat,
 				Healthy: false,
 				Detail:  err.Error(),
 			}, nil
@@ -48,7 +49,7 @@ func (mon *RawHealthMonitor) CheckHealth() (types.HealthCheckResult, error) {
 	}
 	defer conn.Close()
 	return types.HealthCheckResult{
-		Latency: time.Since(start),
+		Latency: lat,
 		Healthy: true,
 	}, nil
 }