fix(templates): use expression attributes and fix indentation

Convert string-interpolation attributes (value="{ x }") to templ
expression attributes (value={ x }) for IDs, paths, and titles, and
fix indentation in header.templ and progress.templ.

templates/admin_library.templ

@@ -78,7 +78,7 @@ templ AdminLibrary(user User, libraries []LibraryData, users []User) {
 								<select id="user-select" onchange="loadUserVisibility()" class="px-3 py-2 border rounded" style="background-color: var(--bg-primary); color: var(--text-primary); border-color: var(--border)">
 									<option value="">Select a user...</option>
 									for _, user := range users {
-										<option value="{ user.ID }">{ user.Username } ({ user.Email })</option>
+										<option value={ user.ID }>{ user.Username } ({ user.Email })</option>
 									}
 								</select>
 							</div>