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/idlewatcher/types/paths.go

@@ -0,0 +1,8 @@
+package idlewatcher
+
+const (
+	FavIconPath        = "/favicon.ico"
+	LoadingPageCSSPath = "/$godoxy/style.css"
+	LoadingPageJSPath  = "/$godoxy/loading.js"
+	WakeEventsPath     = "/$godoxy/wake-events"
+)

internal/idlewatcher/types/waker.go

@@ -1,6 +1,7 @@
 package idlewatcher
 
 import (
+	"context"
 	"net/http"
 
 	nettypes "github.com/yusing/godoxy/internal/net/types"
@@ -11,5 +12,5 @@ type Waker interface {
 	types.HealthMonitor
 	http.Handler
 	nettypes.Stream
-	Wake() error
+	Wake(ctx context.Context) error
 }