Add installation guide and release notes for TimeMachine v2.0.0

- Introduced comprehensive `INSTALL_GUIDE.md` detailing installation methods, system requirements, security checks, and troubleshooting tips.
- Added `RELEASE_NOTES_V2.0.0.md` summarizing major updates, new features, critical bug fixes, UI/UX improvements, and technical enhancements for the v2.0.0 release.
- Updated `build.gradle.kts` to reflect new versioning for the app (version 2.0.0).
- Enhanced documentation to support user onboarding and provide clarity on new functionalities.

Author: aliahadmd

INSTALL_GUIDE.md

@@ -0,0 +1,281 @@
+# TimeMachine v2.0.0 - Installation Guide
+
+## 📱 Quick Installation
+
+### Method 1: Direct Installation (Recommended)
+
+1. **Transfer APK to Device**
+   - Connect your Android device to computer via USB
+   - Copy `TimeMachineV2.0.0.apk` to your device's Downloads folder
+   - Or use ADB: `adb install TimeMachineV2.0.0.apk`
+
+2. **Enable Unknown Sources**
+   - Go to **Settings** → **Security** → **Unknown Sources**
+   - Or **Settings** → **Apps** → **Special Access** → **Install Unknown Apps**
+   - Enable for your file manager or browser
+
+3. **Install**
+   - Open your file manager
+   - Navigate to Downloads
+   - Tap on `TimeMachineV2.0.0.apk`
+   - Tap **Install**
+   - Wait for installation to complete
+   - Tap **Open** to launch
+
+### Method 2: ADB Installation (For Developers)
+
+```bash
+# Connect device via USB with USB debugging enabled
+adb devices
+
+# Install the APK
+adb install -r TimeMachineV2.0.0.apk
+
+# Launch the app
+adb shell am start -n me.aliahad.timemanager/.MainActivity
+```
+
+---
+
+## ✅ System Requirements
+
+- **Android Version**: 12 (API 31) or higher
+- **Storage**: At least 50 MB free space
+- **RAM**: 2 GB or more recommended
+- **Screen**: Any screen size supported
+
+---
+
+## 🔐 Security
+
+### APK Verification
+
+Verify the APK integrity before installation:
+
+```bash
+# Check MD5 hash
+md5 TimeMachineV2.0.0.apk
+# Should output: 624619775c92b2466774015748e20a82
+```
+
+### Signing Information
+
+- **Signed**: ✅ Yes (Release keystore)
+- **Keystore**: `release-keystore.jks`
+- **Key Alias**: `timemanager`
+
+---
+
+## 🚀 First Launch
+
+### Initial Setup
+
+1. **Launch the App**
+   - Tap the TimeMachine icon on your home screen
+   - The app will initialize the database
+
+2. **Grant Permissions (If Needed)**
+   - The app requires minimal permissions
+   - Notification permission (optional, for habit reminders)
+
+3. **Start Using**
+   - **Home Screen**: Shows all available features
+   - **Focus Tracker**: Create categories and start tracking
+   - **Year Calculator**: Calculate dates
+   - **BMI Calculator**: Track your health metrics
+   - **Habit Tracker**: Build better habits
+
+---
+
+## 🎯 Feature Quick Start
+
+### Focus Tracker
+1. Tap **Focus Tracker** on home screen
+2. Go to **Categories** tab
+3. Tap **+ Add Category**
+4. Set name, icon, color, and daily goal
+5. Go back to **Track** tab
+6. Select your category
+7. Tap **Start Focus Session**
+8. Enter immersive fullscreen mode
+9. Double-tap to show/hide controls
+10. Press **STOP** when done (minimum 30s to save)
+
+### Year Calculator
+1. Tap **Year Calculator** on home screen
+2. Select **Birthdate** or **From Date**
+3. Enter number of years
+4. View results instantly
+5. Tap **Save Calculation** to keep history
+
+### BMI Calculator
+1. Tap **BMI Calculator** on home screen
+2. Enter your details:
+   - Age
+   - Height (ft/cm)
+   - Weight (kg/lb)
+   - Gender
+   - Classification system (WHO/DGE)
+3. Tap **Calculate BMI**
+4. View results with graph and recommendations
+5. Tap **Save** to keep history
+
+### Habit Tracker
+1. Tap **Habit Tracker** on home screen
+2. Tap **+** to add new habit
+3. Set name, icon, color
+4. Choose reminder time (optional)
+5. Tap habit card to mark as complete
+6. View streaks and statistics
+
+---
+
+## 🐛 Troubleshooting
+
+### App Won't Install
+
+**Error: "App not installed"**
+- Solution: Uninstall old version first
+- Go to Settings → Apps → TimeMachine → Uninstall
+- Then install the new APK
+
+**Error: "Package conflicts with existing package"**
+- Solution: Clear app data before uninstalling
+- Or use: `adb uninstall me.aliahad.timemanager`
+
+### App Crashes on Launch
+
+**Black screen or immediate crash**
+- Solution 1: Clear app cache and data
+- Solution 2: Restart your device
+- Solution 3: Reinstall the app
+
+**Database error**
+- Solution: The app auto-migrates from older versions
+- If issues persist, clear app data (loses local data)
+
+### Features Not Working
+
+**Sessions not saving**
+- Ensure you track for at least 30 seconds
+- Look for green "✓ Session will be saved" indicator
+- Check if category is selected
+
+**Notifications not showing**
+- Go to Settings → Apps → TimeMachine → Notifications
+- Enable all notification channels
+- Check Do Not Disturb settings
+
+**UI not updating**
+- Pull to refresh if available
+- Close and reopen the app
+- Data refreshes automatically when screens resume
+
+---
+
+## 📊 Data Management
+
+### Backup Your Data
+
+The app stores data locally in a SQLite database:
+- Location: `/data/data/me.aliahad.timemanager/databases/`
+- Database file: `timer_database.db`
+
+To backup (requires root or ADB):
+```bash
+# Backup database
+adb pull /data/data/me.aliahad.timemanager/databases/timer_database.db ./backup.db
+
+# Restore database
+adb push ./backup.db /data/data/me.aliahad.timemanager/databases/timer_database.db
+```
+
+### Clear App Data
+
+If you want to start fresh:
+1. Settings → Apps → TimeMachine
+2. Storage → Clear Data
+3. This will reset everything
+
+---
+
+## 🔄 Updating from Previous Versions
+
+### From v1.x.x to v2.0.0
+
+**Automatic Migration**:
+- Database automatically migrates to version 6
+- Old timer data is preserved (if any)
+- Habits and existing data remain intact
+
+**Manual Steps**:
+1. Install `TimeMachineV2.0.0.apk` over existing version
+2. Or uninstall old version first (loses data)
+3. Launch app
+4. Migration happens automatically on first launch
+
+**What's Changed**:
+- Focus Timer replaced with Focus Tracker
+- New category-based system
+- Old timer sessions (if any) are preserved
+
+---
+
+## 💡 Tips & Tricks
+
+### Focus Tracker
+- Set realistic daily goals (e.g., 60-120 minutes)
+- Use categories for different activities (Work, Study, Exercise)
+- Double-tap in fullscreen to quickly check progress
+- Sessions under 30s won't save (prevents accidental taps)
+
+### Year Calculator
+- Useful for age calculations
+- Perfect for anniversaries and milestones
+- Save important date calculations
+
+### BMI Calculator
+- Track weight changes over time
+- Compare WHO vs DGE classifications
+- Use health tips for guidance
+
+### Habit Tracker
+- Start with 1-3 habits (don't overwhelm yourself)
+- Enable reminders for consistency
+- Celebrate streaks!
+
+---
+
+## 🆘 Support
+
+### Getting Help
+
+1. **Check Release Notes**: Read `RELEASE_NOTES_V2.0.0.md`
+2. **Check Logs**: Use `adb logcat | grep TimeMachine`
+3. **Report Issues**: Contact developer with logs
+
+### Known Issues
+
+- **Deprecation warnings in build**: Cosmetic only, no impact on functionality
+- **Leap year dates**: Handled gracefully, no crashes
+- **Timezone**: All dates use device timezone
+
+---
+
+## 📝 Version Information
+
+- **Version Name**: 2.0.0
+- **Version Code**: 5
+- **Package Name**: me.aliahad.timemanager
+- **Min SDK**: 31 (Android 12)
+- **Target SDK**: 36 (Android 16)
+- **Release Date**: October 20, 2025
+
+---
+
+## 🎉 Enjoy TimeMachine v2.0.0!
+
+Thank you for using TimeMachine. We hope this update brings you better productivity and health tracking!
+
+**Happy Time Managing!** ⏰✨
+