fix: validate parent_id in error path, rebuild Tailwind CSS

- Defensively parse parent_id in _render_htmx_error: coerce to int,
  fallback to main form if non-numeric or parent not found
- Rebuild Tailwind CSS to include new utility classes from templates
- Add test for tampered parent_id falling back to main form

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

apps/comments/tests/test_v2.py

@@ -150,6 +150,20 @@ def test_non_htmx_post_still_redirects(client, _article):
     assert resp["Location"].endswith("?commented=1")
 
 
+@pytest.mark.django_db
+def test_htmx_error_with_tampered_parent_id_falls_back_to_main_form(client, _article):
+    """Tampered/non-numeric parent_id falls back to main form error response."""
+    cache.clear()
+    resp = client.post(
+        "/comments/post/",
+        {"article_id": _article.id, "parent_id": "not-a-number", "author_name": "T",
+         "author_email": "t@t.com", "body": "   ", "honeypot": ""},
+        HTTP_HX_REQUEST="true",
+    )
+    assert resp.status_code == 200
+    assert b"comment-form-container" in resp.content
+
+
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