feat(rules): write-time UI reflexes in web-building.md, from ui-skills

Fourteen lines of stack-agnostic micro-rules (dvh, safe-area, paste,
tabular-nums, text-wrap, z-index scale, compositor-only motion, 44 px
targets, focus-visible, status not by color alone, errors by the field,
one accent per view). Case 3 of the 6-repo review: nothing installed.

CHANGELOG.md

@@ -7,6 +7,14 @@ Format follows [Keep a Changelog](https://keepachangelog.com/).
 ## [Unreleased]
 
 ### Added
+- **rules/web-building.md § Write-time reflexes** — stack-agnostic
+  micro-rules borrowed from ibelick/ui-skills (baseline-ui + playbook): dvh
+  and safe-area, paste never blocked, tabular-nums and text-wrap, one
+  z-index scale, compositor-only motion with reduced-motion and off-screen
+  pause, 44 px targets and focus-visible, status never by color alone,
+  errors next to the field, one accent per view. Case 3 of the 6-repo
+  review: nothing installed (CLI and MCP are a curl of raw SKILL.md, a
+  third router, and baseline-ui's stack mandates contradict Astro-first).
 - **`make test suite=<file>`** runs one suite hermetically; the
   `GIT_CONFIG_GLOBAL=/dev/null` export lives in the Makefile so nobody types
   the denied env-prefix form by hand (the reason an executor wrote a wrapper

rules/web-building.md

@@ -18,6 +18,21 @@ paths: ["**/*.html", "**/*.astro", "**/*.css", "**/*.scss", "**/*.tsx", "**/*.js
 - Inter, Geist or Space Grotesk as the default font: propose an
   alternative and justify it. Existing brand identities keep their fonts.
 
+## Write-time reflexes (stack-agnostic, from ui-skills)
+- Full height: `100dvh`, never `100vh`; fixed elements respect
+  `safe-area-inset`. Never block paste in inputs.
+- Numbers: `tabular-nums`. Headings `text-wrap: balance`, body `pretty`.
+  Long labels: truncate or line-clamp, never overflow.
+- One z-index scale from tokens, no arbitrary values.
+- Motion: transform and opacity only; feedback under 200 ms, ease-out on
+  entrances, never from scale(0); `will-change` only during an active
+  animation; pause loops off-screen; honor `prefers-reduced-motion`.
+- Touch targets 44 px minimum; visible `:focus-visible` ring; status never
+  by color alone, add text or an icon.
+- Errors next to the field; empty state = one clear action; destructive
+  action confirmed first.
+- One accent color per view; solid modal backdrop, no full-screen blur.
+
 ## Before declaring a public site done
 Check: custom 404 · call to action in the first viewport · per-page
 title + description · share/OG image · favicons · robots.txt · sitemap ·