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>

Docs/XCUITest-Authoring.md

@@ -0,0 +1,122 @@
+# XCUITest Authoring Guide
+
+## Architecture
+
+```
+PlantGuideUITests/
+  Foundation/
+    BaseUITestCase.swift     # Base class all tests inherit from
+    UITestID.swift           # Mirrors AccessibilityIdentifiers from the app
+    WaitHelpers.swift        # Centralized predicate-based waits
+  Helpers/
+    XCUIApplication+Launch.swift  # LaunchConfigKey constants
+  Screens/                   # Page/screen objects
+    TabBarScreen.swift
+    CameraScreen.swift
+    CollectionScreen.swift
+    TodayScreen.swift
+    SettingsScreen.swift
+    PlantDetailScreen.swift
+  # Test files (one per feature flow)
+  NavigationUITests.swift
+  CameraFlowUITests.swift
+  CollectionFlowUITests.swift
+  SettingsFlowUITests.swift
+  AccessibilityUITests.swift
+  PlantGuideUITests.swift         # Smoke tests
+  PlantGuideUITestsLaunchTests.swift  # Screenshot capture
+```
+
+## Rules
+
+1. **Every test class inherits `BaseUITestCase`** -- not `XCTestCase`.
+2. **Launch via helpers** -- `launchClean()`, `launchWithMockData()`, `launchOffline()`.
+3. **Locate elements by accessibility identifier** (`UITestID.*`), never by localized text.
+4. **Use screen objects** for navigation and assertions (e.g., `TabBarScreen`, `CollectionScreen`).
+5. **No `sleep()`** -- use `waitForExistence(timeout:)`, `waitUntilHittable()`, or `waitUntilGone()`.
+6. **Tests must be deterministic** -- launch args control fixtures; no dependency on device state.
+7. **One assertion focus per test** -- if testing collection empty state, don't also test search.
+
+## Writing a New Test
+
+### Step 1 - Add identifiers (if needed)
+
+In the app source, add `.accessibilityIdentifier(AccessibilityIdentifiers.Foo.bar)`.
+Mirror the ID in `UITestID.Foo.bar`.
+
+### Step 2 - Create or extend a screen object
+
+```swift
+struct FooScreen {
+    let app: XCUIApplication
+
+    var myButton: XCUIElement {
+        app.buttons[UITestID.Foo.myButton]
+    }
+
+    @discardableResult
+    func waitForLoad(timeout: TimeInterval = 5) -> Bool {
+        app.navigationBars["Foo"].waitForExistence(timeout: timeout)
+    }
+}
+```
+
+### Step 3 - Write the test
+
+```swift
+final class FooFlowUITests: BaseUITestCase {
+
+    @MainActor
+    func testMyFeature() throws {
+        launchWithMockData()
+        let foo = TabBarScreen(app: app).tapFoo()
+        XCTAssertTrue(foo.waitForLoad())
+        foo.myButton.tapWhenReady()
+        // assert...
+    }
+}
+```
+
+### Step 4 - Verify compile
+
+```bash
+xcodebuild build-for-testing \
+  -project PlantGuide.xcodeproj \
+  -scheme PlantGuide \
+  -destination 'platform=iOS Simulator,name=iPhone 17' \
+  -quiet
+```
+
+## Launch Configurations
+
+| Helper              | State        | Data | Network |
+|---------------------|-------------|------|---------|
+| `launchClean()`     | Fresh       | None | Online  |
+| `launchWithMockData()` | Seeded   | Mock | Online  |
+| `launchOffline()`   | Fresh       | None | Offline |
+
+All launchers pass `-UITesting` and `-SkipOnboarding`.
+
+## Wait Helpers (WaitHelpers.swift)
+
+| Method                     | Purpose                              |
+|---------------------------|--------------------------------------|
+| `waitUntilHittable()`     | Element exists AND is tappable       |
+| `waitUntilGone()`         | Element has disappeared              |
+| `waitForValue(_:)`        | Element value matches string         |
+| `tapWhenReady()`          | Wait then tap                        |
+| `app.waitForLaunch()`     | Tab bar appeared after launch        |
+| `app.waitForElement(id:)` | Any descendant by identifier         |
+
+## Tab Labels
+
+The app has 4 tabs. Use `UITestID.TabBar.*`:
+
+| Tab        | Label         |
+|-----------|---------------|
+| Camera    | `"Camera"`    |
+| Collection| `"Collection"`|
+| Today     | `"Today"`     |
+| Settings  | `"Settings"`  |
+
+Note: The third tab is **"Today"** (not "Care").