feat: add mobile image upload support with camera integration

- Added mobile-optimized image upload functionality allowing users to select from camera/gallery
- Updated upload button to support multiple file selection with progress indicator
- Added documentation for mobile upload testing steps in MOBILE_COMPATIBILITY.md
- Expanded mobile compatibility checklist to include camera/gallery upload verification

MOBILE_COMPATIBILITY.md

@@ -74,6 +74,9 @@ The VoxBlog admin interface has been optimized for mobile devices with responsiv
 - **Grid adapts**: 150px min columns on mobile, 200px on desktop
 - Tip text hidden on mobile (xs) to save space
 - Small buttons throughout
+- **📱 Upload button**: Tap to select images from phone camera/gallery
+- Supports multiple file selection
+- Shows upload progress
 
 #### 12. **Recorder** (`features/recorder/Recorder.tsx`)
 - Button toolbar wraps
@@ -131,12 +134,13 @@ Test on these viewport sizes:
 1. **Login** - AuthGate form usable
 2. **Posts List** - Grid scrolls, search works, buttons accessible
 3. **Editor** - Stepper scrolls, sidebar stacks, steps navigate
-4. **Assets** - Media grid adapts, recorder buttons wrap
+4. **Assets** - Media grid adapts, recorder buttons wrap, **upload button works**
 5. **Generate** - Streaming content displays, buttons wrap
 6. **Edit** - Rich editor works, placeholder buttons wrap
 7. **Metadata** - Form fields full-width, buttons wrap
 8. **Publish** - Preview scrolls, buttons wrap
 9. **Settings** - Form usable, buttons stack
+10. **📱 Mobile Upload** - Tap "Upload Images" to select from camera/gallery
 
 ## Browser Compatibility