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/OpenSessions.tsx

@@ -18,7 +18,7 @@ interface OpenSessionsProps {
 export function OpenSessions({ sessions }: OpenSessionsProps) {
   return (
     <div className="card-flat flex flex-col h-full">
-      <div className="flex items-center justify-between px-5 py-3" style={{ borderBottom: '1px solid var(--glass-border)' }}>
+      <div className="flex items-center justify-between px-5 py-3" style={{ borderBottom: '1px solid var(--color-border-default)' }}>
         <h3 className="font-heading text-sm font-bold text-foreground">My Open Sessions</h3>
         <Link to="/sessions" className="text-[0.6875rem] text-muted-foreground hover:text-foreground transition-colors">
           View All
@@ -35,7 +35,7 @@ export function OpenSessions({ sessions }: OpenSessionsProps) {
               key={session.id}
               className="flex items-center gap-3 px-5 py-3"
               style={{
-                borderBottom: i < sessions.length - 1 ? '1px solid var(--glass-border)' : undefined,
+                borderBottom: i < sessions.length - 1 ? '1px solid var(--color-border-default)' : undefined,
               }}
             >
               <span className="h-2 w-2 shrink-0 rounded-full bg-amber-400" />