feat: add UMass Amherst theme support, implement HTML snippet management system, and update page rendering logic

sisvietnamvn_main/replace_footer_logo.py

@@ -0,0 +1,16 @@
+import re
+
+filepath = "src/main/resources/templates/themes/umass/footer.html"
+with open(filepath, "r", encoding="utf-8") as f:
+    content = f.read()
+
+# We want to replace the `a.logo` block with our new logo
+# Using DOTALL to match across newlines
+pattern = r'<a class="logo"[^>]*>.*?</a>'
+replacement = '<a class="logo" href="/" aria-label="Sisvietnamvn">\n  <div>\n    <img th:src="@{/theme-assets/umass/images/logo.png}" alt="Sisvietnamvn" style="height: 60px; width: auto;"/>\n  </div>\n</a>'
+
+content = re.sub(pattern, replacement, content, count=1, flags=re.DOTALL)
+
+with open(filepath, "w", encoding="utf-8") as f:
+    f.write(content)
+print("Updated footer.html")