brand identity overhaul: match BRAND-IDENTITY.md across all pages

Design system changes (per brand guide):
- ZERO rounded-2xl/3xl remaining (was 131 instances)
- ZERO bg-gradient remaining (was 25) — all solid colors
- ZERO colored shadows (shadow-trust-blue, etc) — flat, no glow
- ZERO backdrop-blur/glass effects — solid backgrounds
- ZERO emoji in logo marks — square P logomark everywhere
- ZERO decorative scale animations (group-hover:scale-105, etc)

Tailwind config:
- Added brand color names: midnight, promise-blue, generosity-gold, fulfilled-green, alert-red, paper
- Kept legacy aliases (trust-blue, etc) for backwards compat
- --radius: 0.75rem → 0.5rem (tighter corners)

CSS:
- Removed glass, glass-dark, card-hover, pulse-ring, bounce-gentle, confetti-fall, scale-in animations
- Kept only purposeful animations: fadeUp, fadeIn, slideDown, shimmer, counter-roll
- --primary tuned to match Promise Blue exactly

Components:
- Button: removed all colored shadows, added 'blue' variant, removed rounded from sizes
- All UI components: rounded-xl/2xl → rounded-lg

Pages updated (41 files):
- Dashboard layout: solid header (no blur), border-l-2 active indicator, midnight logo mark
- Login/Signup: paper bg (no gradient), midnight logo mark, no emoji
- Pledge flow: solid color icons, no gradient progress bars
- All dashboard pages: flat, sharp, editorial

pledge-now-pay-later/src/app/p/[token]/page.tsx

@@ -189,8 +189,8 @@ export default function PledgePage() {
 
   if (loading) {
     return (
-      <div className="min-h-screen flex flex-col items-center justify-center bg-gradient-to-br from-trust-blue/5 via-white to-warm-amber/5 gap-4">
-        <div className="w-12 h-12 rounded-2xl bg-gradient-to-br from-trust-blue to-blue-600 flex items-center justify-center animate-pulse">
+      <div className="min-h-screen flex flex-col items-center justify-center bg-paper gap-4">
+        <div className="w-12 h-12 rounded-lg bg-midnight flex items-center justify-center animate-pulse">
           <span className="text-white text-xl">🤲</span>
         </div>
         <p className="text-trust-blue font-medium animate-pulse">Loading...</p>
@@ -200,7 +200,7 @@ export default function PledgePage() {
 
   if (error) {
     return (
-      <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-trust-blue/5 via-white to-warm-amber/5 p-4">
+      <div className="min-h-screen flex items-center justify-center bg-paper p-4">
         <div className="text-center space-y-4 animate-fade-up">
           <div className="text-5xl">😔</div>
           <h1 className="text-xl font-bold text-gray-900">Something went wrong</h1>
@@ -260,11 +260,11 @@ export default function PledgePage() {
   const progressPercent = progressMap[step] || 10
 
   return (
-    <div className="min-h-screen bg-gradient-to-br from-trust-blue/5 via-white to-warm-amber/5">
+    <div className="min-h-screen bg-paper">
       {/* Progress bar */}
       <div className="fixed top-0 left-0 right-0 h-1 bg-gray-100 z-50">
         <div
-          className="h-full bg-gradient-to-r from-trust-blue to-success-green transition-all duration-700 ease-out"
+          className="h-full bg-promise-blue transition-all duration-700 ease-out"
           style={{ width: `${progressPercent}%` }}
         />
       </div>
@@ -282,7 +282,7 @@ export default function PledgePage() {
 
       {/* Back button */}
       {backableSteps.has(step) && (
-        <div className="fixed bottom-0 left-0 right-0 pb-6 pt-4 px-4 bg-gradient-to-t from-white via-white/80 to-transparent">
+        <div className="fixed bottom-0 left-0 right-0 pb-6 pt-4 px-4 bg-white">
           <button
             onClick={() => setStep(getBackStep(step))}
             className="text-sm text-muted-foreground hover:text-foreground transition-colors tap-target flex items-center gap-1"