feat: Rebrand frontend from Patherly to ResolutionFlow

- Add brand assets (favicon, icons, logos) to public/icons and src/assets/brand
- Update index.html with new favicon, title, meta, Google Fonts (Plus Jakarta Sans, Inter, Outfit)
- Add brand colors, font families, and gradient utilities to Tailwind config
- Replace CSS variables with purple-tinted theme for both light and dark modes
- Create reusable BrandLogo and BrandWordmark components
- Update AppLayout header with logo and wordmark
- Update LoginPage and RegisterPage with branded logo, wordmark, and gradient buttons
- Replace all remaining "Patherly" references in SettingsPage

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/layout/AppLayout.tsx

@@ -1,6 +1,8 @@
 import { Link, useLocation, useNavigate, Outlet } from 'react-router-dom'
 import { useAuthStore } from '@/store/authStore'
 import { ThemeToggle } from '@/components/common/ThemeToggle'
+import { BrandLogo } from '@/components/common/BrandLogo'
+import { BrandWordmark } from '@/components/common/BrandWordmark'
 import { cn } from '@/lib/utils'
 
 export function AppLayout() {
@@ -22,11 +24,12 @@ export function AppLayout() {
   return (
     <div className="min-h-screen bg-background">
       {/* Header */}
-      <header className="sticky top-0 z-50 border-b border-border bg-card">
-        <div className="container mx-auto flex h-14 items-center justify-between px-4">
+      <header className="sticky top-0 z-50 border-b border-border bg-card backdrop-blur-sm">
+        <div className="container mx-auto flex h-16 items-center justify-between px-4">
           <div className="flex items-center gap-8">
-            <Link to="/trees" className="text-lg font-bold text-foreground">
-              Patherly
+            <Link to="/trees" className="flex items-center gap-2">
+              <BrandLogo size="sm" />
+              <BrandWordmark size="sm" />
             </Link>
             <nav className="hidden items-center gap-1 sm:flex">
               {navItems.map((item) => (