feat: implement chat history, theme customization, and password management

- Added chat history persistence for active rooms with auto-cleanup on stream end.
- Overhauled Settings page with user profile, theme color picker, and password change.
- Added backend API for user password updates.
- Integrated flutter_launcher_icons and updated app icon to 'H' logo.
- Fixed 'Duplicate keys' bug in danmaku by using UniqueKey and filtering historical messages.
- Updated version to 1.0.0-beta3.5 and author info.

backend/internal/stream/server.go

@@ -11,6 +11,7 @@ import (
 	"github.com/nareix/joy4/format"
 	"github.com/nareix/joy4/format/rtmp"
 
+	"hightube/internal/chat"
 	"hightube/internal/db"
 	"hightube/internal/model"
 )
@@ -83,6 +84,10 @@ func NewRTMPServer() *RTMPServer {
 			q.Close()
 			// Explicitly set is_active to false using map
 			db.DB.Model(&room).Updates(map[string]interface{}{"is_active": false})
+			
+			// Clear chat history for this room
+			chat.MainHub.ClearRoomHistory(fmt.Sprintf("%d", room.ID))
+			
 			fmt.Printf("[INFO] Publishing ended for Room ID: %d\n", room.ID)
 		}()