Add README with features, tech stack, and usage docs

README.md

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+# Ledga
+
+M-Pesa spending tracker for Android. Automatically reads M-Pesa SMS confirmations to track your spending — zero manual entry.
+
+## Download
+
+Download the latest APK from [Releases](https://github.com/ngenohkevin/ledga/releases/latest).
+
+Install directly on your Android phone (no Play Store needed). The app checks for updates automatically.
+
+## Features
+
+### Automatic SMS Tracking
+- Reads M-Pesa SMS in real-time via BroadcastReceiver
+- Supports **17 transaction types**: Send Money, Buy Goods, Pay Bill, Withdraw (Agent/ATM), Deposit, Received, Airtime (Self/Other), M-Pesa Global, Fuliza (Borrow/Repayment/Reversal), M-Shwari, KCB M-Pesa, Reversal
+- Import existing SMS history on first launch
+- Stores raw SMS for future parser improvements
+
+### Smart Categorization
+- 13 default categories: Groceries, Transport, Bills, Airtime, Food, Send Money, Received, Withdrawal, Deposit, Shopping, International, Savings & Loans, Other
+- Auto-categorizes by merchant name and paybill/till number
+- Pre-loaded rules for common merchants (Naivas, KPLC, Uber, etc.)
+- Tap any transaction to re-categorize
+
+### Home Dashboard
+- Current M-Pesa balance (from last transaction)
+- Monthly spending total with fees breakdown
+- Animated donut chart by category
+- Period selector: Today / This Week / Month
+- Recent transactions feed
+
+### Transactions
+- Grouped by day with search and filters
+- Filter by type: All, Sent, Received, Bills, Goods, Withdraw
+- Transaction detail bottom sheet with full info
+- One-tap re-categorization
+
+### Trends & Analytics
+- Daily spending bar chart (Vico)
+- Category breakdown with color indicators
+- Top 5 merchants by spending
+- Transaction fees summary
+- Period selector: 7D / 30D / 90D / 1Y
+
+### Budget Tracking
+- Set overall monthly budget
+- Progress bars with color coding (green/warning/red)
+- Per-category budget support
+
+### Notifications
+- Daily spending summary (default 8 PM)
+- Weekly summary (Sunday evening)
+- Budget warning at 80% and exceeded at 100%
+- Large transaction alerts (configurable threshold)
+- All toggleable in settings
+
+### Backup & Export
+- **Google Drive**: Auto-backup to app data folder, restore on fresh install
+- **Manual Export**: ZIP file with `transactions.csv` (Excel-friendly) + `data.json` (full restore)
+- **Manual Import**: Restore from exported ZIP
+- Share exports via WhatsApp, email, Bluetooth
+
+### Self-Update
+- Checks GitHub Releases on launch (max once per day)
+- Download and install updates directly from the app
+
+### Customization
+- Theme: System / Light / Dark
+- Font size: System Default / Small / Medium / Large / Extra Large
+- M-Pesa green primary color with Material 3
+
+## Tech Stack
+
+| Component | Technology |
+|-----------|------------|
+| Language | Kotlin |
+| UI | Jetpack Compose + Material 3 |
+| Database | Room (SQLite) |
+| DI | Hilt |
+| Settings | Jetpack DataStore |
+| Charts | Vico |
+| Background | WorkManager + BroadcastReceiver |
+| Backup | Google Drive API |
+| Navigation | Navigation Compose (type-safe routes) |
+| Build | Gradle (Kotlin DSL) |
+
+## Requirements
+
+- Android 8.0+ (API 26)
+- SMS permission (to read M-Pesa messages)
+- Notification permission (Android 13+, for summaries and alerts)
+
+## Privacy
+
+All data stays on your device. No server, no accounts, no analytics, no tracking. Google Drive backup uses the app-specific folder — invisible to other apps and only accessible by Ledga.
+
+## Building
+
+```bash
+# Debug
+./gradlew assembleDebug
+
+# Release (requires keystore)
+./gradlew assembleRelease
+
+# Tests
+./gradlew testDebugUnitTest
+```
+
+## Release
+
+Tag a version to trigger the CI/CD pipeline:
+
+```bash
+git tag v1.0.0
+git push origin v1.0.0
+```
+
+GitHub Actions builds the signed APK and creates a release automatically.
+
+## License
+
+Private — for personal/family use.