Update source code with grid layout and channel management

Major changes:
- Add ChannelAdapter for grid display functionality
- Add ChannelRepository for data management
- Add PlayerActivity for dedicated video playback
- Add StreamChannel model for channel representation
- Update MainActivity to support grid layout
- Update activity_main.xml with grid UI components
- Add channel item layouts and drawables
- Update AndroidManifest.xml with new activity
- Update build.gradle dependencies

This implements the requested "grilla arreglada" functionality with proper channel grid display and management.

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

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

app/src/main/AndroidManifest.xml

@@ -15,12 +15,17 @@
         android:theme="@style/Theme.StreamPlayer"
         android:usesCleartextTraffic="true">
 
+        <activity
+            android:name=".PlayerActivity"
+            android:exported="false"
+            android:screenOrientation="landscape" />
+
         <activity
             android:name=".MainActivity"
-            android:exported="true"
-            android:screenOrientation="landscape">
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
+
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>