fix(landing): design audit fixes — hamburger menu, dead links, branding, spacing (#117)

* fix(landing): design audit fixes — hamburger menu, dead links, branding, spacing

- Add mobile hamburger menu with animated open/close and click-outside dismiss
- Create Privacy and Terms pages (footer links were dead # anchors)
- Change "Decision Tree Platform" to "AI-Powered Troubleshooting for MSPs" on login, register, and HTML title
- Fix register page icon color (was red/coral via CSS invert, now uses BrandLogo directly)
- Replace "0 Ticket Notes Written by Hand" stat with "100% Auto-Generated Documentation"
- Increase nav link touch targets to 44px minimum
- Fix heading hierarchy: section titles are now <h2>, standardize H3 to 1.25rem
- Tighten section spacing (6rem → 4rem padding, remove extra 5rem spacer)
- Add color-scheme: dark to HTML element
- Replace all transition: all with specific properties (10 occurrences)
- Fix loading ellipsis (... → …)

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

* fix(mobile): responsive modals + landing preview overflow

- PrepareSessionModal: bottom-sheet on mobile, centered on desktop
- IntakeFormModal: bottom-sheet on mobile, responsive padding
- ShareTreeModal: bottom-sheet on mobile, full-width on small screens
- Landing preview: hide URL bar and window controls on mobile (<900px)
  to prevent 189px horizontal overflow

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

* fix(mobile): collapse search bar to icon on mobile

On mobile (<640px), the full search bar with placeholder text and ⌘K
badge was taking too much space in the topbar. Now shows just a
magnifying glass icon that opens the same command palette on tap.

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

---------

Co-authored-by: chihlasm <michael@resolutionflow.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/layout/TopBar.tsx

@@ -78,10 +78,10 @@ export function TopBar() {
         {/* Spacer - push search to center */}
         <div className="flex-1" />
 
-        {/* Search trigger */}
+        {/* Search trigger — icon on mobile, full bar on desktop */}
         <button
           onClick={() => setCommandPaletteOpen(true)}
-          className="relative w-full text-left"
+          className="hidden sm:relative sm:block w-full text-left"
           style={{ maxWidth: '480px' }}
         >
           <Search size={16} className="absolute left-3 top-1/2 -translate-y-1/2 text-muted-foreground" />
@@ -92,6 +92,13 @@ export function TopBar() {
             {navigator.platform?.toLowerCase().includes('mac') ? '⌘K' : 'Ctrl+K'}
           </span>
         </button>
+        <button
+          onClick={() => setCommandPaletteOpen(true)}
+          className="sm:hidden rounded-lg p-2 text-muted-foreground hover:bg-card hover:text-foreground transition-colors"
+          title="Search"
+        >
+          <Search size={18} />
+        </button>
 
         {/* Spacer - push actions to right */}
         <div className="flex-1" />