fix: resolve review round 2, E2E failures, and mypy error

Review blocker A — form error swap and false success:
- Change HTMX contract so forms target their own container (outerHTML)
  instead of appending to #comments-list
- Use OOB swaps to append approved comments to the correct target
- Add success/error message display inside form templates
- Remove hx-on::after-request handlers (no longer needed)

Review blocker B — reply rendering shape:
- Create _reply.html partial with compact reply markup
- Approved replies via HTMX now use compact template + OOB swap
  into parent's .replies-container
- Reply form errors render inside reply form container

E2E test fixes:
- Update 4 failing tests to wait for inline HTMX messages instead
  of redirect-based URL assertions
- Add aria-label='Comment form errors' to form error display
- Rename test_reply_submission_redirects to
  test_reply_submission_shows_moderation_message

Mypy internal error workaround:
- Add mypy override for apps.comments.views (django-stubs triggers
  internal error on ORM annotate() chain with mypy 1.11.2)

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

apps/comments/tests/test_v2.py

@@ -67,30 +67,37 @@ def _post_comment(client, article, extra=None, htmx=False):
 
 
 @pytest.mark.django_db
-def test_htmx_post_returns_partial_on_success(client, _article):
-    """HTMX POST with Turnstile disabled returns moderation notice partial."""
+def test_htmx_post_returns_form_with_moderation_on_success(client, _article):
+    """HTMX POST with Turnstile disabled returns fresh form + moderation message."""
     resp = _post_comment(client, _article, htmx=True)
     assert resp.status_code == 200
     assert b"awaiting moderation" in resp.content
+    # Response swaps the form container (contains form + success message)
+    assert b"comment-form-container" in resp.content
     assert "HX-Request" in resp["Vary"]
 
 
 @pytest.mark.django_db
 @override_settings(TURNSTILE_SECRET_KEY="test-secret")
-def test_htmx_post_returns_comment_partial_when_turnstile_passes(client, _article):
-    """HTMX POST with successful Turnstile returns comment partial for append."""
+def test_htmx_post_returns_form_plus_oob_comment_when_approved(client, _article):
+    """HTMX POST with successful Turnstile returns fresh form + OOB comment."""
     with patch("apps.comments.views._verify_turnstile", return_value=True):
         resp = _post_comment(client, _article, extra={"cf-turnstile-response": "tok"}, htmx=True)
     assert resp.status_code == 200
-    assert b"Hello world" in resp.content
-    assert b"comment-" in resp.content
+    content = resp.content.decode()
+    # Fresh form container is the primary response
+    assert "comment-form-container" in content
+    assert "Comment posted!" in content
+    # OOB swap appends the comment to #comments-list
+    assert "hx-swap-oob" in content
+    assert "Hello world" in content
     comment = Comment.objects.get()
     assert comment.is_approved is True
 
 
 @pytest.mark.django_db
 def test_htmx_post_returns_form_with_errors_on_invalid(client, _article):
-    """HTMX POST with invalid data returns form partial with HTTP 200 (HTMX 2 requires 2xx for swap)."""
+    """HTMX POST with invalid data returns form with errors (HTTP 200)."""
     cache.clear()
     resp = client.post(
         "/comments/post/",
@@ -98,10 +105,43 @@ def test_htmx_post_returns_form_with_errors_on_invalid(client, _article):
         HTTP_HX_REQUEST="true",
     )
     assert resp.status_code == 200
+    assert b"comment-form-container" in resp.content
+    assert b"Comment form errors" in resp.content
     assert "HX-Request" in resp["Vary"]
     assert Comment.objects.count() == 0
 
 
+@pytest.mark.django_db
+@override_settings(TURNSTILE_SECRET_KEY="test-secret")
+def test_htmx_reply_returns_oob_reply_when_approved(client, _article, approved_comment):
+    """Approved reply via HTMX returns compact reply partial via OOB swap."""
+    cache.clear()
+    with patch("apps.comments.views._verify_turnstile", return_value=True):
+        resp = client.post(
+            "/comments/post/",
+            {
+                "article_id": _article.id,
+                "parent_id": approved_comment.id,
+                "author_name": "Replier",
+                "author_email": "r@r.com",
+                "body": "Nice reply",
+                "honeypot": "",
+                "cf-turnstile-response": "tok",
+            },
+            HTTP_HX_REQUEST="true",
+        )
+    content = resp.content.decode()
+    assert resp.status_code == 200
+    # OOB targets the parent's replies-container
+    assert f"#comment-{approved_comment.id}" in content
+    assert "hx-swap-oob" in content
+    # Reply uses compact markup (no nested reply form)
+    assert "Reply posted!" in content
+    reply = Comment.objects.exclude(pk=approved_comment.pk).get()
+    assert reply.parent_id == approved_comment.id
+    assert reply.is_approved is True
+
+
 @pytest.mark.django_db
 def test_non_htmx_post_still_redirects(client, _article):
     """Non-HTMX POST continues to redirect (progressive enhancement)."""