Add Telegram notification integration for geofencing

Features:
- Multi-channel notifications (Email + Telegram)
- User-configurable notification settings per channel
- Telegram bot integration with rich messages, location pins, and inline buttons
- QR code generation for easy bot access (@myidbot support)
- Admin UI for notification settings management
- Test functionality for Telegram connection
- Comprehensive documentation

Implementation:
- lib/telegram-service.ts: Telegram API integration
- lib/notification-settings-db.ts: Database layer for user notification preferences
- lib/geofence-notifications.ts: Extended for parallel multi-channel delivery
- API routes for settings management and testing
- Admin UI with QR code display and step-by-step instructions
- Database table: UserNotificationSettings

Documentation:
- docs/telegram.md: Technical implementation guide
- docs/telegram-anleitung.md: User guide with @myidbot instructions
- docs/telegram-setup.md: Admin setup guide
- README.md: Updated NPM scripts section

Docker:
- Updated Dockerfile to copy public directory
- Added TELEGRAM_BOT_TOKEN environment variable
- Integrated notification settings initialization in db:init

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/notification-settings-db.ts

@@ -0,0 +1,157 @@
+import Database from 'better-sqlite3';
+import path from 'path';
+
+const dbPath = path.join(process.cwd(), 'data', 'database.sqlite');
+
+export interface UserNotificationSettings {
+  user_id: string;
+  email_enabled: boolean;
+  telegram_enabled: boolean;
+  telegram_chat_id: string | null;
+  created_at?: string;
+  updated_at?: string;
+}
+
+/**
+ * Get notification settings for a user
+ * Returns default settings if not found
+ */
+export function getUserNotificationSettings(
+  userId: string
+): UserNotificationSettings {
+  const db = new Database(dbPath);
+  try {
+    const stmt = db.prepare(`
+      SELECT
+        user_id,
+        email_enabled,
+        telegram_enabled,
+        telegram_chat_id,
+        created_at,
+        updated_at
+      FROM UserNotificationSettings
+      WHERE user_id = ?
+    `);
+
+    const result = stmt.get(userId) as any;
+
+    // Return defaults if no settings found
+    if (!result) {
+      return {
+        user_id: userId,
+        email_enabled: true,
+        telegram_enabled: false,
+        telegram_chat_id: null,
+      };
+    }
+
+    // Convert SQLite integers to booleans
+    return {
+      user_id: result.user_id,
+      email_enabled: result.email_enabled === 1,
+      telegram_enabled: result.telegram_enabled === 1,
+      telegram_chat_id: result.telegram_chat_id,
+      created_at: result.created_at,
+      updated_at: result.updated_at,
+    };
+  } finally {
+    db.close();
+  }
+}
+
+/**
+ * Update notification settings for a user
+ */
+export function updateUserNotificationSettings(
+  userId: string,
+  settings: Partial<UserNotificationSettings>
+): UserNotificationSettings {
+  const db = new Database(dbPath);
+  try {
+    // Check if settings exist
+    const existing = db
+      .prepare('SELECT user_id FROM UserNotificationSettings WHERE user_id = ?')
+      .get(userId);
+
+    if (existing) {
+      // Update existing
+      const updates: string[] = [];
+      const values: any[] = [];
+
+      if (settings.email_enabled !== undefined) {
+        updates.push('email_enabled = ?');
+        values.push(settings.email_enabled ? 1 : 0);
+      }
+      if (settings.telegram_enabled !== undefined) {
+        updates.push('telegram_enabled = ?');
+        values.push(settings.telegram_enabled ? 1 : 0);
+      }
+      if (settings.telegram_chat_id !== undefined) {
+        updates.push('telegram_chat_id = ?');
+        values.push(settings.telegram_chat_id);
+      }
+
+      updates.push('updated_at = datetime(\'now\')');
+      values.push(userId);
+
+      const stmt = db.prepare(`
+        UPDATE UserNotificationSettings
+        SET ${updates.join(', ')}
+        WHERE user_id = ?
+      `);
+
+      stmt.run(...values);
+    } else {
+      // Insert new
+      const stmt = db.prepare(`
+        INSERT INTO UserNotificationSettings (
+          user_id,
+          email_enabled,
+          telegram_enabled,
+          telegram_chat_id
+        ) VALUES (?, ?, ?, ?)
+      `);
+
+      stmt.run(
+        userId,
+        settings.email_enabled !== undefined ? (settings.email_enabled ? 1 : 0) : 1,
+        settings.telegram_enabled !== undefined ? (settings.telegram_enabled ? 1 : 0) : 0,
+        settings.telegram_chat_id ?? null
+      );
+    }
+
+    return getUserNotificationSettings(userId);
+  } finally {
+    db.close();
+  }
+}
+
+/**
+ * Initialize notification settings table
+ */
+export function initNotificationSettingsTable(): void {
+  const db = new Database(dbPath);
+  try {
+    db.exec(`
+      CREATE TABLE IF NOT EXISTS UserNotificationSettings (
+        user_id TEXT PRIMARY KEY,
+        email_enabled INTEGER DEFAULT 1,
+        telegram_enabled INTEGER DEFAULT 0,
+        telegram_chat_id TEXT,
+        created_at TEXT DEFAULT (datetime('now')),
+        updated_at TEXT DEFAULT (datetime('now')),
+
+        FOREIGN KEY (user_id) REFERENCES User(id) ON DELETE CASCADE,
+        CHECK (email_enabled IN (0, 1)),
+        CHECK (telegram_enabled IN (0, 1))
+      );
+
+      CREATE INDEX IF NOT EXISTS idx_user_notification_settings_user
+        ON UserNotificationSettings(user_id);
+    `);
+
+    console.log('✓ UserNotificationSettings table initialized');
+  } finally {
+    db.close();
+  }
+}