feat(notion-writer): add GitHub-alert callout blocks

Adds support for > [!NOTE] / > [!TIP] / > [!IMPORTANT] / > [!WARNING] /
> [!CAUTION] callouts. Each alert type maps to a Notion callout block
with an emoji icon and matching colored background. Unknown alert types
(e.g. > [!BOGUS]) fall through to the existing quote handler with the
marker preserved.

Also restores the "must come before generic bullet match" comment on
the todo branch (load-bearing ordering note).

+6 tests, 22 passing total.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

custom-skills/32-notion-writer/code/scripts/notion_writer.py

@@ -122,6 +122,7 @@ def _parse_lines(lines: List[str]) -> List[Dict[str, Any]]:
                 code_lines.append(lines[i])
                 i += 1
             blocks.append(create_code_block('\n'.join(code_lines), language))
+        # Checkbox / Todo (must come before generic bullet match)
         elif line.strip().startswith('- [ ]'):
             text = line.strip()[5:].strip()
             blocks.append(create_todo_block(text, False))
@@ -134,9 +135,21 @@ def _parse_lines(lines: List[str]) -> List[Dict[str, Any]]:
         elif re.match(r'^\d+\.\s', line.strip()):
             text = re.sub(r'^\d+\.\s', '', line.strip())
             blocks.append(create_numbered_list_block(text))
+        # Blockquote — GitHub-alert callout takes priority over generic quote
         elif line.startswith('>'):
-            text = line[1:].strip()
-            blocks.append(create_quote_block(text))
+            first_body = line[1:].strip()
+            alert_match = ALERT_RE.match(first_body)
+            if alert_match:
+                alert_type = alert_match.group(1)
+                body_lines: List[str] = []
+                i += 1
+                while i < len(lines) and lines[i].lstrip().startswith('>'):
+                    body_lines.append(lines[i].lstrip()[1:].lstrip())
+                    i += 1
+                body_text = '\n'.join(body_lines)
+                blocks.append(create_callout_block(body_text, alert_type))
+                continue
+            blocks.append(create_quote_block(first_body))
         elif line.strip() in ['---', '***', '___']:
             blocks.append(create_divider_block())
         else:
@@ -155,6 +168,15 @@ INLINE_PATTERNS = [
     ('italic_under',  re.compile(r'(?<![a-zA-Z0-9_])_([^_\n]+)_(?![a-zA-Z0-9_])')),
 ]
 
+ALERT_TYPES = {
+    'NOTE':      ('ℹ️', 'blue_background'),
+    'TIP':       ('💡', 'green_background'),
+    'IMPORTANT': ('☝️', 'purple_background'),
+    'WARNING':   ('⚠️', 'yellow_background'),
+    'CAUTION':   ('🚨', 'red_background'),
+}
+ALERT_RE = re.compile(r'^\s*\[!(NOTE|TIP|IMPORTANT|WARNING|CAUTION)\]\s*$')
+
 
 _ABSOLUTE_URL_RE = re.compile(r'^(?:[a-zA-Z][a-zA-Z0-9+.-]*:)')
 
@@ -292,6 +314,19 @@ def create_quote_block(text: str) -> Dict[str, Any]:
     }
 
 
+def create_callout_block(text: str, alert_type: str) -> Dict[str, Any]:
+    """Create a callout block with icon + color from a GitHub alert type."""
+    icon, color = ALERT_TYPES[alert_type]
+    return {
+        "type": "callout",
+        "callout": {
+            "rich_text": parse_rich_text(text),
+            "icon": {"type": "emoji", "emoji": icon},
+            "color": color,
+        },
+    }
+
+
 def create_code_block(code: str, language: str) -> Dict[str, Any]:
     return {
         "object": "block",