feat: initial project scaffold — server, client, Android APK

- FastAPI server with audio mixer (Windows + Voicemeeter), media tracking,
  notifications (progress + alerts), telemetry, and system tray .exe build
- Test suite covering notifications, audio mixer, media, telemetry, and API
- E-Ink web client (vanilla JS, DOM API, block meters, swipe gestures)
- Android WebView APK for BOOX Go 7 Color Gen II (Android 13, Kotlin)
- Design decision records in .pi/docs/design/
- PyInstaller build script for server .exe

.gitignore

@@ -0,0 +1,50 @@
+# Dependencies
+__pycache__/
+*.py[cod]
+*.egg-info/
+dist/
+build/
+.eggs/
+*.so
+*.spec
+
+# Virtual environments
+venv/
+.venv/
+env/
+.env/
+
+# Environment variables
+.env
+.env.local
+.env.production
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Project config (contains secrets, PINs, tokens)
+.pi/
+
+# Build artifacts
+*.exe
+*.pyc
+*.pyo
+
+# Linter caches
+.ruff_cache/
+
+# Android
+android/.gradle/
+android/build/
+android/app/build/
+*.apk
+*.aab
+android/local.properties