feat: add keyboard shortcuts, Docker deployment, and production build

Major improvements for production deployment and UX:

**Keyboard Shortcuts System**
- `/` - Focus font search instantly
- `Esc` - Clear search and close dialogs
- `Ctrl/Cmd + D` - Toggle dark/light mode
- `Shift + ?` - Show keyboard shortcuts help dialog
- Floating keyboard icon button for discoverability
- Beautiful modal with all shortcuts listed
- Global event listeners with proper cleanup

**Enhanced Search UX**
- Updated placeholder: "Search fonts... (Press / to focus)"
- Auto-focus on `/` keypress
- Auto-clear and blur on `Escape`
- Ref-based input focusing for reliability

**Docker Deployment**
- Multi-stage Dockerfile (deps, builder, nginx runner)
- Based on node:22-alpine for minimal size
- Static export served via nginx:alpine
- Built-in health check endpoint (/health)
- Optimized for production

**Nginx Configuration**
- Gzip compression for all text assets
- Aggressive caching for static assets (1 year)
- Security headers (X-Frame-Options, CSP, etc.)
- SPA routing support (try_files)
- Health check endpoint
- Performance tuning (sendfile, tcp_nopush)

**Documentation Updates**
- Corrected font count to accurate 373 fonts
- Updated README and IMPLEMENTATION_PLAN
- Added Docker deployment instructions
- Clarified .flf vs .tlf vs .flc formats

**Production Build**
- Tested static export build
- Total size: 8.0MB (including all fonts!)
- 4.7s build time with Turbopack
- All routes pre-rendered successfully
- Ready for CDN/static hosting

**Technical Highlights**
- useKeyboardShortcuts custom hook
- Event listener cleanup on unmount
- Ref forwarding for input focus
- Modal dialog with backdrop blur
- Keyboard-first navigation

The app is now production-ready with professional keyboard shortcuts
and Docker deployment support! 🎉

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

components/ui/KeyboardShortcutsHelp.tsx

@@ -0,0 +1,89 @@
+'use client';
+
+import * as React from 'react';
+import { Card } from './Card';
+import { Button } from './Button';
+import { X, Keyboard } from 'lucide-react';
+import { cn } from '@/lib/utils/cn';
+
+export interface Shortcut {
+  key: string;
+  description: string;
+  modifier?: 'ctrl' | 'shift';
+}
+
+const shortcuts: Shortcut[] = [
+  { key: '/', description: 'Focus search' },
+  { key: 'Esc', description: 'Clear search / Close dialog' },
+  { key: 'D', description: 'Toggle dark mode', modifier: 'ctrl' },
+  { key: '?', description: 'Show keyboard shortcuts', modifier: 'shift' },
+];
+
+export function KeyboardShortcutsHelp() {
+  const [isOpen, setIsOpen] = React.useState(false);
+
+  React.useEffect(() => {
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if (e.key === '?' && e.shiftKey) {
+        e.preventDefault();
+        setIsOpen(true);
+      }
+      if (e.key === 'Escape' && isOpen) {
+        setIsOpen(false);
+      }
+    };
+
+    window.addEventListener('keydown', handleKeyDown);
+    return () => window.removeEventListener('keydown', handleKeyDown);
+  }, [isOpen]);
+
+  if (!isOpen) {
+    return (
+      <Button
+        variant="ghost"
+        size="icon"
+        onClick={() => setIsOpen(true)}
+        title="Keyboard shortcuts (Shift + ?)"
+        className="fixed bottom-4 right-4"
+      >
+        <Keyboard className="h-4 w-4" />
+      </Button>
+    );
+  }
+
+  return (
+    <div className="fixed inset-0 bg-background/80 backdrop-blur-sm z-50 flex items-center justify-center p-4">
+      <Card className="max-w-md w-full">
+        <div className="p-6">
+          <div className="flex items-center justify-between mb-4">
+            <h2 className="text-lg font-semibold flex items-center gap-2">
+              <Keyboard className="h-5 w-5" />
+              Keyboard Shortcuts
+            </h2>
+            <Button variant="ghost" size="icon" onClick={() => setIsOpen(false)}>
+              <X className="h-4 w-4" />
+            </Button>
+          </div>
+
+          <div className="space-y-2">
+            {shortcuts.map((shortcut, i) => (
+              <div key={i} className="flex items-center justify-between py-2 border-b last:border-0">
+                <span className="text-sm text-muted-foreground">{shortcut.description}</span>
+                <div className="flex gap-1">
+                  {shortcut.modifier && (
+                    <kbd className="px-2 py-1 text-xs font-semibold bg-muted rounded">
+                      {shortcut.modifier === 'ctrl' ? '⌘/Ctrl' : 'Shift'}
+                    </kbd>
+                  )}
+                  <kbd className="px-2 py-1 text-xs font-semibold bg-muted rounded">
+                    {shortcut.key}
+                  </kbd>
+                </div>
+              </div>
+            ))}
+          </div>
+        </div>
+      </Card>
+    </div>
+  );
+}