feat(Settings): add Language and Hardware Acceleration selectors in Preferences

- Language dropdown (System/en/es/fr/de/ja/zh) persists to convertConfig.Language.
- Hardware Acceleration dropdown persists to convertConfig.HardwareAccel.
- Replace placeholder with working controls.
- Keep Preferences tab logically grouped; avoid menu surfing.

Note: No runtime language switching yet; selection persisted for future implementation.

This change provides user control of global defaults independent of benchmark,
and maintains decoupling introduced by benchmark refactor.

DONE.md

@@ -17,7 +17,7 @@
 
 ### Maintenance
 - ✅ **Git author cleanup**
-  - Rewrote commit history to set commits to "Stu Leak <leaktechnologies@proton.me>" for consistent attribution.
+  - Rewrote commit history to ensure consistent commit attribution.
 - ✅ **Installer dependency parity**
   - Ensured pip is installed (Linux/Windows) and skipped Go/pip installs when already present.
 
@@ -125,7 +125,7 @@ This file tracks completed features, fixes, and milestones.
   - Queue onChange callback now handles all refreshes automatically - removed duplicate manual calls
   - Added stopQueueAutoRefresh() before navigation to prevent conflicting UI updates
   - Result: Instant button response on Windows (was 1-3 second lag)
-  - Reported by: contributor
+  - Reported by: user report
 
 - ✅ **Main Menu Performance**
   - Fixed main menu lag when sidebar visible and queue active
@@ -249,7 +249,7 @@ This file tracks completed features, fixes, and milestones.
   - Added `-MaximumRedirection 10` to handle SourceForge redirects
   - Added browser user agent to prevent rejection
   - Resolves "invalid archive" error on Windows 11
-  - Reported by: contributor
+  - Reported by: user report
 
 ### Technical Improvements
 - ✅ **Responsive Design Pattern**
@@ -476,7 +476,7 @@ This file tracks completed features, fixes, and milestones.
   - Preserved window size before/after SetContent() calls
   - User retains full control via manual resize or maximize
   - Improves professional appearance and stability
-  - Reported by: contributor
+  - Reported by: user report
 
 ### Features (2025-12-18 Session)
 - ✅ **History Sidebar Enhancements**

TODO.md

@@ -2,6 +2,11 @@
 
 This file tracks upcoming features, improvements, and known issues.
 
+## Maintenance
+
+- [X] **Installer dependency parity**
+  - Ensure pip is installed on Linux/Windows and skip Go/pip when already present.
+
 ## Documentation: Fix Structural Errors
 
 **Priority:** High

docs/CROSS_PLATFORM_GUIDE.md

@@ -245,7 +245,7 @@ The `scripts/test-cross-platform.sh` script provides:
 
 ## 🎯 Benefits Achieved
 
-### For You (Arch Linux)
+### Arch Linux Notes
 - ✅ **Perfect Arch Integration**: Detects your exact setup
 - ✅ **GPU Optimization**: Proper driver recommendations  
 - ✅ **Desktop Awareness**: GNOME/KDE/XFCE specific handling

settings_module.go

@@ -557,12 +557,25 @@ func buildPreferencesTab(state *appState) fyne.CanvasObject {
 	header.TextStyle = fyne.TextStyle{Bold: true}
 	content.Add(header)
 
-	content.Add(widget.NewLabel("Preferences panel - Coming soon"))
-	content.Add(widget.NewLabel("This will include settings for:"))
-	content.Add(widget.NewLabel("• Default output directories"))
-	content.Add(widget.NewLabel("• Default encoding presets"))
-	content.Add(widget.NewLabel("• UI theme preferences"))
-	content.Add(widget.NewLabel("• Automatic updates"))
+	// Language selection (persisted UI language)
+	langLabel := widget.NewLabel("Language")
+	langSelect := widget.NewSelect([]string{"System", "en", "es", "fr", "de", "ja", "zh"}, func(selected string) {
+		state.convert.Language = selected
+		state.persistConvertConfig()
+	})
+	langSelect.SetSelected(state.convert.Language)
+	content.Add(container.NewVBox(langLabel, langSelect))
+
+	content.Add(widget.NewSeparator())
+
+	// Hardware acceleration default (used globally and by benchmark)
+	hwLabel := widget.NewLabel("Hardware Acceleration")
+	hwSelect := widget.NewSelect([]string{"auto", "none", "nvenc", "qsv", "amf", "vaapi", "videotoolbox"}, func(selected string) {
+		state.convert.HardwareAccel = selected
+		state.persistConvertConfig()
+	})
+	hwSelect.SetSelected(state.convert.HardwareAccel)
+	content.Add(container.NewVBox(hwLabel, hwSelect))
 
 	return content
 }