test(coverage): enforce API and app floors

Measure untouched mobile source, add regression coverage for native media paths and account operations, and enforce ratcheting API and mobile thresholds in required CI checks.

apps/mobile/jest.config.js

@@ -17,6 +17,21 @@ module.exports = {
         '<rootDir>/src/**/__tests__/**/*.(spec|test).(ts|tsx)',
         '<rootDir>/src/**/*.(spec|test).(ts|tsx)',
     ],
+    collectCoverageFrom: [
+        '<rootDir>/app/**/*.{ts,tsx}',
+        '<rootDir>/src/**/*.{ts,tsx}',
+        '!<rootDir>/src/**/__tests__/**',
+        '!<rootDir>/src/test/**',
+        '!<rootDir>/**/*.d.ts',
+    ],
+    coverageThreshold: {
+        global: {
+            statements: 23,
+            branches: 17,
+            functions: 21,
+            lines: 23,
+        },
+    },
     transformIgnorePatterns: [
         'node_modules/(?!(jest-)?react-native|@react-native|@react-navigation|expo(nent)?|@expo(nent)?/.*|expo-router|react-native-reanimated|react-native-gesture-handler|react-native-safe-area-context|@sentry/react-native|@sentry/.*)',
     ],