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/pages/LandingPage.tsx

@@ -194,7 +194,7 @@ export default function LandingPage() {
               <div className="landing-preview-body">
                 <div className="landing-preview-sidebar">
                   <div className="landing-preview-sidebar-item active">
-                    <div className="dot" style={{ background: '#22d3ee' }} />
+                    <div className="dot" style={{ background: '#f97316' }} />
                     FlowPilot
                   </div>
                   <div className="landing-preview-sidebar-item">
@@ -221,15 +221,15 @@ export default function LandingPage() {
                       <span className="text">User can&apos;t access shared drive after password reset</span>
                     </div>
                     <div className="landing-mock-chat-line">
-                      <span className="label" style={{ color: '#22d3ee' }}>FlowPilot:</span>
+                      <span className="label" style={{ color: '#f97316' }}>FlowPilot:</span>
                       <span className="text">This is likely a cached credential issue. Let&apos;s check a few things:</span>
                     </div>
                     <div className="landing-mock-chat-line">
-                      <span className="label" style={{ color: '#22d3ee' }}>FlowPilot:</span>
+                      <span className="label" style={{ color: '#f97316' }}>FlowPilot:</span>
                       <span className="text">1. Run <code>klist purge</code> to clear Kerberos tickets</span>
                     </div>
                     <div className="landing-mock-chat-line">
-                      <span className="label" style={{ color: '#22d3ee' }}>FlowPilot:</span>
+                      <span className="label" style={{ color: '#f97316' }}>FlowPilot:</span>
                       <span className="text">2. Open Credential Manager &rarr; remove saved entries for the share</span>
                     </div>
                     <div className="landing-mock-chat-line doc">