Close all 25 codex audit findings across KMP, iOS, and Android

Remediate all P0-S priority findings from cross-platform architecture audit:
- Harden token storage with EncryptedSharedPreferences (Android) and Keychain (iOS)
- Add SSL pinning and certificate validation to API clients
- Fix subscription cache race conditions and add thread-safe access
- Add input validation for document uploads and file type restrictions
- Refactor DocumentApi to use proper multipart upload flow
- Add rate limiting awareness and retry logic to API layer
- Harden subscription tier enforcement in SubscriptionHelper
- Add biometric prompt for sensitive actions (Login, Onboarding)
- Fix notification permission handling and device registration
- Add UI test infrastructure (page objects, fixtures, smoke tests)
- Add CI workflow for mobile builds

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

iosApp/CaseraUITests/TestConfiguration/TestLaunchConfig.swift

@@ -0,0 +1,64 @@
+import XCTest
+
+/// Centralized app launch configuration for UI tests.
+///
+/// Provides consistent launch arguments and environment variables across
+/// all test suites. Disables animations and sets locale to English for
+/// deterministic test behavior.
+enum TestLaunchConfig {
+
+    /// Standard launch arguments for UI test mode.
+    /// Disables animations and forces English locale.
+    static let standardArguments: [String] = [
+        "-UITEST_MODE", "1",
+        "-AppleLanguages", "(en)",
+        "-AppleLocale", "en_US",
+        "-UIAnimationsEnabled", "NO"
+    ]
+
+    /// Launch environment variables for UI tests.
+    static let standardEnvironment: [String: String] = [
+        "UITEST_MODE": "1",
+        "ANIMATIONS_DISABLED": "1"
+    ]
+
+    /// Configure and launch app with standard test settings.
+    ///
+    /// - Parameters:
+    ///   - additionalArguments: Extra launch arguments to append.
+    ///   - additionalEnvironment: Extra environment variables to merge.
+    /// - Returns: The launched `XCUIApplication` instance.
+    @discardableResult
+    static func launchApp(
+        additionalArguments: [String] = [],
+        additionalEnvironment: [String: String] = [:]
+    ) -> XCUIApplication {
+        let app = XCUIApplication()
+        app.launchArguments = standardArguments + additionalArguments
+        var env = standardEnvironment
+        additionalEnvironment.forEach { env[$0.key] = $0.value }
+        app.launchEnvironment = env
+        app.launch()
+        return app
+    }
+
+    /// Launch app pre-authenticated (skips login flow).
+    ///
+    /// Passes test credentials via launch arguments and environment so the
+    /// app can bypass the normal authentication flow during UI tests.
+    ///
+    /// - Parameters:
+    ///   - email: Test user email address.
+    ///   - token: Test authentication token.
+    /// - Returns: The launched `XCUIApplication` instance.
+    @discardableResult
+    static func launchAuthenticated(
+        email: String = "test@example.com",
+        token: String = "test-token-12345"
+    ) -> XCUIApplication {
+        return launchApp(
+            additionalArguments: ["-TEST_AUTH_EMAIL", email, "-TEST_AUTH_TOKEN", token],
+            additionalEnvironment: ["TEST_AUTH_EMAIL": email, "TEST_AUTH_TOKEN": token]
+        )
+    }
+}