refactor: replace cyan accent with ember orange across entire frontend

Swap accent color from cyan (#22d3ee) to ember orange (#f97316) site-wide.
Cyan caused contrast issues and felt generic — orange brings warmth and
urgency fitting for a troubleshooting tool.

Changes:
- CSS variables: accent, accent-hover, accent-dim, accent-text, primary, ring
- Warning color shifted from amber (#fbbf24) to yellow (#eab308) for
  semantic separation from orange accent
- Brand SVGs: logo gradient updated to orange
- 50+ component files: all hardcoded cyan hex values, Tailwind cyan-*
  classes, and rgba(34,211,238,...) glow values replaced
- landing.css: all 45+ cyan references + 5 old border color fixes
- DESIGN-SYSTEM.md bumped to v5 with decisions log
- CLAUDE.md: all color references synced to charcoal palette + orange accent
- PWA theme-color meta tag updated to match sidebar (#10121a)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/assets/brand/icon.svg

@@ -1,8 +1,8 @@
 <svg viewBox="0 0 80 80" fill="none" xmlns="http://www.w3.org/2000/svg">
   <defs>
     <linearGradient id="resolutionflow-gradient" x1="0%" y1="0%" x2="100%" y2="0%">
-      <stop offset="0%" stop-color="#06b6d4"/>
-      <stop offset="100%" stop-color="#22d3ee"/>
+      <stop offset="0%" stop-color="#ea580c"/>
+      <stop offset="100%" stop-color="#f97316"/>
     </linearGradient>
   </defs>
   <!-- Input circles (choices) -->

frontend/src/assets/brand/logo-horizontal.svg

@@ -1,8 +1,8 @@
 <svg viewBox="0 0 320 80" fill="none" xmlns="http://www.w3.org/2000/svg">
   <defs>
     <linearGradient id="rf-gradient" x1="0%" y1="0%" x2="100%" y2="0%">
-      <stop offset="0%" stop-color="#06b6d4"/>
-      <stop offset="100%" stop-color="#22d3ee"/>
+      <stop offset="0%" stop-color="#ea580c"/>
+      <stop offset="100%" stop-color="#f97316"/>
     </linearGradient>
   </defs>
   

frontend/src/assets/brand/logo-with-tagline.svg

@@ -1,8 +1,8 @@
 <svg viewBox="0 0 320 100" fill="none" xmlns="http://www.w3.org/2000/svg">
   <defs>
     <linearGradient id="rf-gradient-tag" x1="0%" y1="0%" x2="100%" y2="0%">
-      <stop offset="0%" stop-color="#06b6d4"/>
-      <stop offset="100%" stop-color="#22d3ee"/>
+      <stop offset="0%" stop-color="#ea580c"/>
+      <stop offset="100%" stop-color="#f97316"/>
     </linearGradient>
   </defs>