docs(governance): require Playwright for frontend changes

docs/release-control/internal/AGENT_VALUES.md

@@ -105,7 +105,8 @@ that already belong to the canonical system.
 18. Treat browser truth as product truth for customer surfaces.
    Code-level proof matters, but customer-facing surfaces are not acceptable
    until real in-browser behavior and interaction quality are good enough to
-   deserve normal use.
+   deserve normal use. When a slice changes frontend code, inspect the changed
+   surface in Playwright before calling that slice progress or done.
 
 ## Delegation Rule
 

docs/release-control/internal/CONTROL_PLANE.md

@@ -146,6 +146,12 @@ model that active and future release profiles reuse.
    untrustworthy in real browser use, the control plane should steer the
    agent toward redesigning the owning model or boundary instead of
    continuing narrow same-shape iteration on that weak baseline.
+21. Frontend slices require browser proof at the browser layer.
+   For frontend or UI changes, a build and code-level tests are not enough to
+   call the slice progress. The changed surface must be exercised in
+   Playwright after the current build, and that browser inspection should
+   inform whether the slice is acceptable, still prototype-grade, or needs a
+   deeper redesign.
 
 ## Canonical Files
 

docs/release-control/v6/internal/CANONICAL_DEVELOPMENT_PROTOCOL.md

@@ -267,7 +267,9 @@ Every substantial task must finish by checking these questions:
     For important customer-facing UI, code-level proof is not enough by
     itself. If the surface is meant to be trusted or used normally, exercise
     it in-browser and judge whether it actually deserves more iteration in its
-    current shape.
+    current shape. If the slice changed frontend code, inspect the changed
+    surface in Playwright after the current build before treating the work as
+    progress, improvement, or done.
     They are not the work item by themselves unless the remaining gap is
     explicitly governance-only.
     For ordinary lane work, identify the runtime, product, ownership, or