detector: hover-state contrast + color-mix/compositing, radial-halo rule, top/bottom stripe variant, file:// browser scans

Four changes driven by human design review of eval artifacts:

1. Static engine contrast fidelity (nav-CTA cascade miss):
   - parseAnyColor evaluates color-mix() (premultiplied sRGB mix; exact
     for the dominant `color-mix(in oklab, C n%, transparent)` chip form)
   - extractStaticColor captures color-mix() balanced instead of plucking
     "transparent" out of the expression
   - resolveBackground composites translucent layers over the opaque base
     in both engines instead of skipping (static) or returning them
     as-if-opaque (browser)
   - NEW hover pass in the static cascade: :hover rules are matched via
     state-stripped selectors, merged per-property against the resting
     cascade with real specificity, and checked for WCAG contrast on
     styled controls (checkHoverContrast). Catches the recurring miss
     where a broader selector (.nav-links a:hover) beats the CTA's own
     hover color and drops the pair below AA.

2. New `radial-halo` slop rule: chromatic radial-gradient wash (visible
   saturated center -> transparent) as a decorative background on a dark
   page. Exempts achromatic vignettes, opaque-end sheens, px-stop dot
   textures, url() photo layers, and translucent (<0.7 alpha) staged-
   light washes. Separate id from dark-glow so dashboards track the
   gradient-drawn variant independently.

3. side-tab horizontal variant: 3-12px chromatic border-top/bottom (and
   top/bottom-anchored full-width pseudo stripes) on cards/badges flag as
   side-tab. Exempt: tablist/nav/aria-selected underlines, link/button
   affordances, table cells, hr, state-conditional pseudo stripes, and
   >12px bands. Badge-shaped spans (own visible background) participate.

4. CLI: file:// URLs route to the Puppeteer browser engine (~2s on a
   50KB page), and detect --json findings now carry the registry
   `category` field so downstream QA loops can separate mechanical slop
   tells from judgment calls.

Fixture policy update: flat 3px top-accent cards moved from should-pass
to flag columns; tablist-underline and 16px-band pass cases added.
Browser bundle regenerated.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

cli/engine/registry/antipatterns.mjs

@@ -122,6 +122,15 @@ const ANTIPATTERNS = [
     skillSection: 'Color & Contrast',
     skillGuideline: 'dark mode with glowing accents',
   },
+  {
+    id: 'radial-halo',
+    category: 'slop',
+    name: 'Radial-gradient background halo',
+    description:
+      'A chromatic radial-gradient wash — saturated at the center, fading to transparent — used as a decorative background glow on a dark page. Same tell as glowing shadows, drawn with a gradient instead of a shadow. Ground the surface with a solid or subtly shifted background instead.',
+    skillSection: 'Color & Contrast',
+    skillGuideline: 'dark mode with glowing accents',
+  },
   {
     id: 'icon-tile-stack',
     category: 'slop',