claim(3 U1): app screenshot wired + captured — uptime-kuma working UI no-secrets, graceful degradation; gate CLAIMED

machine-docs/JOURNAL-3.md

@@ -99,3 +99,36 @@ None on failure) — then the card's `show_shot` gate falls back to the `no scre
 as the fail fixture already proves. No renderer change needed.
 
 Not claiming U2 — still parked at the U0 gate per §6.1 (no advance past a gate without its PASS).
+
+## 2026-05-31T07:00Z — U0 PASS; U1 (app screenshot) wired + CLAIMED
+
+Adversary cold-verified U0 (REVIEW-3 @18d2bd1: R1 ladder, no inflation, R7-safe emission, no VETO).
+Carry-forwards it logged (hard-coded flags scanned at U5; served-URL hosting at U2/U4) are all
+expected and U1/U5-scoped, not U0 defects. Proceeded past U0 to U1.
+
+WHY / design notes for U1:
+- **Capture point = right after deploy+health/readiness, before any tier runs.** Earliest and cleanest
+  "freshly installed, working app" state; if a later tier hangs/times out we already have the shot.
+  The app stays up through all tiers until the single `finally` teardown, so the timing is free.
+- **Placed OUTSIDE the deploy try/except**, guarded by `if deploy_ok`. Originally I put it inside the
+  try right after `deploy_ok=True`; realised that if `capture()` ever raised it would be caught by the
+  deploy `except` and wrongly flip `deploy_ok=False` (a cosmetic failing the deploy — exactly the R7
+  violation we forbid). Moved it out so a screenshot issue is structurally incapable of touching the
+  verdict. `capture()` is also internally all-swallowing, so it's belt-and-suspenders.
+- **Secret-safety = landing page by default.** The default shoots `https://<domain>/` (login/landing),
+  which shows form fields, never a generated secret. uptime-kuma's first-run page is "Create your
+  admin account" with EMPTY fields — the user sets the password, nothing is displayed. Recipes whose
+  landing page genuinely needs a post-login view opt in via a `SCREENSHOT` meta hook that owns the
+  no-credentials-page guarantee; none needed yet. The harness NEVER auto-fills a setup wizard.
+- **results.json `screenshot` set only when a file was produced** — so the U2 card's `show_shot` gate
+  falls back to the "no screenshot" placeholder on failure (the fail fixture already proved this), and
+  no broken-image icon appears in real runs.
+- **Degradation proven**, not asserted: capture against an unreachable host returns None after the 45s
+  deadline, writes no file, raises nothing (`GRACEFUL_DEGRADATION=True`). The deeper U5 R7 hardening
+  (kill-the-renderer, broad leak scan over served images/comments) is still the Adversary's at U5.
+
+Verification (all on cc-ci @5fa15d4):
+- 38 phase-3 unit tests pass (incl. 4 test_screenshot pure-helper tests).
+- uptime-kuma real install run → 30KB screenshot.png of the working UI (empty cred fields), results.json
+  `screenshot="screenshot.png"`, clean_teardown=true, no orphan service.
+- unreachable-host capture → None, no file, no raise.