feat: point prototype and visualization at /user-interface:write-css

.changes/prototype/feat-write-css-pointers-8ecebbbb.md

@@ -0,0 +1,7 @@
+---
+bump: patch
+---
+
+### Changed
+
+- `explore-directions` points real-stack variant CSS at `/user-interface:write-css` when that skill is installed; HTML mockups keep their declared directions.

.changes/visualization/feat-write-css-pointers-c8b686d4.md

@@ -0,0 +1,7 @@
+---
+bump: patch
+---
+
+### Changed
+
+- `visualize` points hand-authored CSS and SVG styling outside the page chrome at `/user-interface:write-css` when that skill is installed.

plugins/prototype/skills/explore-directions/SKILL.md

@@ -197,6 +197,8 @@ it leaves room (and always on the HTML mockup substrate) each variant also decla
 direction rather than sharing one default aesthetic. If two drafts come out too similar, redo one
 with an explicit constraint ("do not use a card grid").
 
+On the real stack, when `/user-interface:write-css` is installed, use it to write each variant's CSS, since it applies the project's design system and conventions first; without it, write the CSS here. The HTML mockup has no project styling to defer to, so write its CSS here from each variant's declared direction.
+
 ### 3. Wire them together
 
 A single switcher component on the route. Framework-idiomatic routing. Use the `?variant=` param

plugins/visualization/skills/visualize/SKILL.md

@@ -88,6 +88,8 @@ fall back to a simple, honest default (a labeled bar/line as inline SVG on a
 page, or a Unicode bar/sparkline in the terminal) and say the craft capability was
 unavailable.
 
+When the form hand-authors CSS or SVG styling outside the page chrome (Step 3) and `/user-interface:write-css` is installed, use it to write that CSS, since it applies the project's design system and conventions first; without it, write the CSS here. The page chrome stays governed by the bundled chrome reference either way.
+
 When the form is a hand-tweakable visual layout, render this skill's rich page
 (or the local file or terminal form Step 3's medium pins) and offer the person the
 design canvas. The canvas is the bundled `design` skill, which is reserved for the