fix: eliminate deprecated cyan, glass-border, and off-palette colors site-wide

- Replace all rgba(6,182,212,...) cyan focus borders and accents with
  rgba(249,115,22,...) ember orange across 21+ component files
- Remove all var(--glass-border) references (undefined variable) with
  var(--color-border-default) across 24 files
- Remove deprecated blur orbs and glass-morphism effects from
  SurveyPage, SurveyThankYouPage, and LoginPage
- Migrate landing.css from hardcoded hex to CSS custom properties
  (~97 replacements for single-source theming)
- Fix off-palette grays in FlowPilotAnalyticsPage chart styling
  (#8891a0 → #848b9b, #18191f → var(--color-bg-card))
- Update stale comments: "cyan brand" → "accent brand" in GlowEdge,
  "gradient cyan square" → "gradient orange square" in BrandLogo
- Rename glow-cyan SVG filter ID to glow-accent
- Fix category color comment: "cyan" → "deep orange"

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

frontend/src/components/dashboard/KnowledgeBaseCards.tsx

@@ -23,7 +23,7 @@ export function KnowledgeBaseCards() {
     <div className="card-flat">
       <div
         className="flex items-center justify-between px-5 py-3"
-        style={{ borderBottom: '1px solid var(--glass-border)' }}
+        style={{ borderBottom: '1px solid var(--color-border-default)' }}
       >
         <h3 className="font-heading text-sm font-bold text-foreground">Knowledge Base</h3>
         <button
@@ -33,7 +33,7 @@ export function KnowledgeBaseCards() {
           Browse <ArrowRight size={10} />
         </button>
       </div>
-      <div className="grid grid-cols-3 divide-x" style={{ borderColor: 'var(--glass-border)' }}>
+      <div className="grid grid-cols-3 divide-x" style={{ borderColor: 'var(--color-border-default)' }}>
         {items.map((item) => (
           <button
             key={item.label}