Rebuild UI test foundation with page objects, wait helpers, and screen objects

Replace brittle localized-string selectors and broken wait helpers with a
robust, identifier-first UI test infrastructure. All 41 UI tests pass on
iOS 26.2 simulator (iPhone 17).

Foundation:
- BaseUITestCase with deterministic launch helpers (launchClean, launchOffline)
- WaitHelpers (waitUntilHittable, waitUntilGone, tapWhenReady) replacing sleep()
- UITestID enum mirroring AccessibilityIdentifiers from the app target
- Screen objects: TabBarScreen, CameraScreen, CollectionScreen, TodayScreen,
  SettingsScreen, PlantDetailScreen

Key fixes:
- Tab navigation uses waitForExistence+tap instead of isHittable (unreliable
  in iOS 26 simulator)
- Tests handle real app state (empty collection, no camera permission)
- Increased timeouts for parallel clone execution
- Added NetworkMonitorProtocol and protocol-typed DI for testability
- Fixed actor-isolation issues in unit test mocks

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

PlantGuideUITests/Screens/CameraScreen.swift

@@ -0,0 +1,48 @@
+//
+//  CameraScreen.swift
+//  PlantGuideUITests
+//
+//  Screen object for the Camera tab.
+//
+
+import XCTest
+
+struct CameraScreen {
+    let app: XCUIApplication
+
+    // MARK: - Elements
+
+    var captureButton: XCUIElement {
+        app.buttons[UITestID.Camera.captureButton]
+    }
+
+    var permissionDeniedView: XCUIElement {
+        app.otherElements[UITestID.Camera.permissionDeniedView]
+    }
+
+    var openSettingsButton: XCUIElement {
+        app.buttons[UITestID.Camera.openSettingsButton]
+    }
+
+    var previewView: XCUIElement {
+        app.otherElements[UITestID.Camera.previewView]
+    }
+
+    // MARK: - State Checks
+
+    /// Returns `true` if any valid camera state is visible (authorized, denied, or requesting).
+    func hasValidState(timeout: TimeInterval = 5) -> Bool {
+        captureButton.waitForExistence(timeout: timeout)
+            || permissionDeniedView.waitForExistence(timeout: 2)
+            // Fallback: look for any text that hints at camera permission
+            || app.staticTexts.matching(
+                NSPredicate(format: "label CONTAINS[c] 'camera'")
+            ).firstMatch.waitForExistence(timeout: 2)
+    }
+
+    // MARK: - Actions
+
+    func tapCapture() {
+        captureButton.tapWhenReady()
+    }
+}