[0xLeif]

Main UI CI sent synthetic Slice gestures before the deferred redraw finished, using clipped canvas bounds as the complete grid. This could miss the first touch edit or select the wrong cell. The helpers now wait for rendered grid dimensions and queued frames, then target cells on the full virtual scroll surface. Exact source, CRLF/download, Undo/history and navigation assertions are unchanged; the viewer runtime and site pin stay unchanged.

Validation:

• Unmodified main reproduced two failures in 30 focused Linux checks; the repair passed 90/90 without retries.
• Full Linux Chromium/WebKit suite: 250 passed, eight existing CI snapshot skips, no retries (official Playwright 1.61.1 Ubuntu Noble ARM64 container).
• Full macOS Chromium/WebKit suite: 258 passed, no retries or skips.
• Strict approved-change SpecSync verification passed. Pinned Fledge 1.7.2 / Trust 1.2.2 passed all eight verification steps, four strict specs and 55/55 source coverage; Augur proceed, risk 24.
• Exact-head hosted UI run 38094598438 passed against e07f832: 250 passed, eight existing skips, no retries or flaky tests (7.1 minutes). Both engines covered all 293 catalog documents across 48 axes.
• Hosted Trust, Linux and Sculpt checks passed. Actions, JavaScript, Python and Rust scans passed; the Swift scan is still running at this update.

Failure: main UI run 38090326009. Detailed reproduction and suite receipts are in docs/evidence/viewer-context/README.md. Actual unsigned agent:codex provenance was recorded and pushed for all three feature commits after the gate passed. Standalone Attest verification rejects the unchanged signature requirement and reviewer allow-list; configured progressive Trust passed with that degradation. No trusted signature, human diff review or lifecycle acceptance/archive is claimed.