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/dashboard/settings/page.tsx

@@ -66,7 +66,7 @@ export default function SettingsPage() {
         <p className="text-sm text-muted-foreground mt-0.5">Configure your organisation&apos;s payment details and integrations</p>
       </div>
 
-      {error && <div className="rounded-xl bg-danger-red/10 border border-danger-red/20 p-3 text-sm text-danger-red">{error}</div>}
+      {error && <div className="rounded-lg bg-danger-red/10 border border-danger-red/20 p-3 text-sm text-danger-red">{error}</div>}
 
       {/* WhatsApp — MOST IMPORTANT, first */}
       <WhatsAppPanel />
@@ -194,7 +194,7 @@ function WhatsAppPanel() {
         </CardHeader>
         <CardContent>
           <div className="flex items-center gap-4">
-            <div className="w-12 h-12 rounded-full bg-[#25D366]/10 flex items-center justify-center">
+            <div className="w-12 h-12 rounded-lg bg-[#25D366]/10 flex items-center justify-center">
               <Smartphone className="h-6 w-6 text-[#25D366]" />
             </div>
             <div>
@@ -240,7 +240,7 @@ function WhatsAppPanel() {
               <div className="relative">
                 {/* Crop to QR area: the screenshot shows full WhatsApp web page. 
                     QR code is roughly in center. We use overflow hidden + object positioning. */}
-                <div className="w-72 h-72 rounded-xl border-2 border-[#25D366]/20 overflow-hidden bg-white">
+                <div className="w-72 h-72 rounded-lg border-2 border-[#25D366]/20 overflow-hidden bg-white">
                   {/* eslint-disable-next-line @next/next/no-img-element */}
                   <img
                     src={qrImage}
@@ -254,7 +254,7 @@ function WhatsAppPanel() {
                 </div>
               </div>
             ) : (
-              <div className="w-72 h-72 rounded-xl border-2 border-dashed border-muted flex items-center justify-center">
+              <div className="w-72 h-72 rounded-lg border-2 border-dashed border-muted flex items-center justify-center">
                 <Loader2 className="h-8 w-8 text-muted-foreground animate-spin" />
               </div>
             )}
@@ -285,9 +285,9 @@ function WhatsAppPanel() {
         </CardDescription>
       </CardHeader>
       <CardContent>
-        <div className="rounded-xl bg-muted/50 p-4 space-y-3">
+        <div className="rounded-lg bg-muted/50 p-4 space-y-3">
           <div className="flex items-start gap-3">
-            <div className="w-10 h-10 rounded-full bg-[#25D366]/10 flex items-center justify-center flex-shrink-0">
+            <div className="w-10 h-10 rounded-lg bg-[#25D366]/10 flex items-center justify-center flex-shrink-0">
               <Smartphone className="h-5 w-5 text-[#25D366]" />
             </div>
             <div>