Rename frontend template references: Bookmann → Bookhoard

Template changes:
- Update page titles: "Bookmann" → "Bookhoard"
- Update header branding and navigation text
- Regenerate compiled .go templates from .templ sources
- Update all UI references in HTML templates

This is part 3 of the project rename to Bookhoard.

templates/header.templ

@@ -7,7 +7,7 @@ templ Header(user User, currentPath string) {
                 <!-- Left: App Title & Navigation -->
                 <div class="flex items-center space-x-6">
                     <a href="/bookshelf" class="text-xl font-bold hover:opacity-80 transition-opacity" style="color: var(--text-primary); text-decoration: none;">
-                        📚 Bookmann
+                        📚 Bookhoard
                     </a>
                     <div class="hidden md:flex items-center space-x-4">
                         <a href="/bookshelf" class="text-sm hover:opacity-80 transition-opacity" style="color: var(--text-secondary); text-decoration: none;">