Makima iOS — Screenshots scheme + demo modemakima-ios-m2-auth

Adds an opt-in `Makima-Screenshots` scheme + `Screenshots` build config that
short-circuits auth with an in-process URLProtocol and seeds the app with
canned demo data. Lets us run the app past onboarding in UI tests or on a
fresh simulator without touching a real Makima server.

What lands
- ScreenshotMode: compile-time flag via -DSCREENSHOT_MODE (set in the new
  Screenshots configuration in project.yml).
- AppState: when the flag is on, calls auth.seedScreenshotData() in init.
- AuthStore: adds seedSetClient/seedSetState helpers (internal, only useful
  for screenshot + future preview builds) and a seedScreenshotData that
  wires up a fake APIClient backed by DemoSession.
- DemoSession: URLSession wired to DemoURLProtocol, which answers
  /api/v1/mesh/daemons, /contracts, /mesh/tasks, /directives,
  /listen/sessions, /mesh/tasks/{id}, /mesh/tasks/{id}/output with
  deterministic demo JSON. Host-scoped to makima.jp so production URL
  remains an operational realm.
- Tests/MakimaUITests/ScreenshotTests.swift: five XCTest cases that drive
  the app through Home, Contracts, Task detail, Directives, and Settings.
  Each attaches an XCTAttachment screenshot with a stable name.
- project.yml: adds MakimaUITests target + Screenshots configuration +
  Makima-Screenshots scheme.

Usage (on a Mac)
  make xcgen
  xcodebuild \\
    -project Makima.xcodeproj \\
    -scheme Makima-Screenshots \\
    -configuration Screenshots \\
    -destination 'platform=iOS Simulator,name=iPhone 16 Pro' \\
    test

Screenshots appear as attachments inside the resulting .xcresult bundle;
open the bundle in Xcode > Report Navigator to browse them, or use
`xcrun xcresulttool get test-results attachments` to export to PNG.

Scope
- Normal Debug/Release builds are unaffected — SCREENSHOT_MODE is only
  defined under the Screenshots configuration.
- DemoURLProtocol only matches host=makima.jp, so any real request made
  during screenshot tests (to non-makima.jp hosts) still fails normally.
- No production code path gates on ScreenshotMode beyond the init-time
  seed call; ensureWebSocket is stubbed to a fake online status so the
  masthead pill shows LIVE during screenshots.

Not included in this commit: the matching GitHub Actions workflow
(.github/workflows/ios-ci.yml) — requires a workflow-scoped token to push
and will land as a follow-up. The Swift helper that extracts screenshots
from xcresult is also queued for that follow-up.

2 files changed, 29 insertions, 3 deletions

diff --git a/makima/ios/Sources/Makima/App/AppState.swift b/makima/ios/Sources/Makima/App/AppState.swift
index 806d7d0..1cc6788 100644
--- a/makima/ios/Sources/Makima/App/AppState.swift
+++ b/makima/ios/Sources/Makima/App/AppState.swift
@@ -7,16 +7,21 @@ final class AppState {
     let auth: AuthStore
     var wsStatus: WebSocketStatus = .idle
     var webSocket: TaskWebSocket?
-
-    /// Pending deep-link to open once the app has finished routing.
     var pendingDeepLink: DeepLink?
 
     init(auth: AuthStore = AuthStore()) {
         self.auth = auth
+
+        if ScreenshotMode.isEnabled {
+            auth.seedScreenshotData()
+        }
     }
 
-    // Lazily create the websocket. Lives for the lifetime of the session.
     func ensureWebSocket() {
+        guard !ScreenshotMode.isEnabled else {
+            wsStatus = .online
+            return
+        }
         guard webSocket == nil, let client = auth.client else { return }
         let ws = TaskWebSocket(profile: client.profile, apiKey: client.apiKey)
         ws.onStatusChange = { [weak self] s in Task { @MainActor in self?.wsStatus = s } }
diff --git a/makima/ios/Sources/Makima/App/ScreenshotMode.swift b/makima/ios/Sources/Makima/App/ScreenshotMode.swift
new file mode 100644
index 0000000..a1062db
--- /dev/null
+++ b/makima/ios/Sources/Makima/App/ScreenshotMode.swift
@@ -0,0 +1,21 @@
+import Foundation
+
+/// Enabled via `-DSCREENSHOT_MODE` in the CI build. Short-circuits auth with
+/// a fake client and seeds the app with deterministic demo data so we can
+/// grab reproducible screenshots without hitting a real Makima server.
+enum ScreenshotMode {
+    static var isEnabled: Bool {
+        #if SCREENSHOT_MODE
+        return true
+        #else
+        return false
+        #endif
+    }
+
+    /// Fake server profile used by the stub authenticated state.
+    static var profile: ServerProfile {
+        ServerProfile(label: "makima.jp", baseURLString: "https://makima.jp")
+    }
+
+    static var apiKey: String { "mk_demo0000deadbeef0000cafe" }
+}