feat(shot): mattermost-lts SCREENSHOT hook → /login (default lands the desktop-or-browser interstitial; watch-list wants the real sign-in form) + public screenshot.settle() for hooks; unit test via real loader; 206 unit tests pass, lint PASS

tests/mattermost-lts/recipe_meta.py

@@ -18,3 +18,22 @@ HEALTH_OK = (200, 302)
 DEPLOY_TIMEOUT = 900
 HTTP_TIMEOUT = 600
 EXTRA_ENV = {"TIMEOUT": "600"}
+
+
+def SCREENSHOT(page, ctx):
+    """Land the real sign-in form for the CI card (phase-shot). The default landing capture gets
+    mattermost's "view in desktop app or browser?" interstitial at `/` — a real page but not
+    representative of the app. `/login` renders the standard login form directly. Credential-free
+    (empty fields, R7 secret-safety: never a page showing generated secrets); the harness snaps
+    the PNG after this returns."""
+    from harness import browser as harness_browser
+    from harness import screenshot as screenshot_mod
+
+    harness_browser.goto_with_retry(
+        page,
+        f"{ctx.base_url}/login",
+        accept_statuses=(200,),
+        deadline_seconds=screenshot_mod.NAV_DEADLINE_S,
+        wait_until="domcontentloaded",
+    )
+    screenshot_mod.settle(page)