feat: migrate README parser to markdown-it-py and refresh website

Switch readme_parser.py from regex-based parsing to markdown-it-py for
more robust and maintainable Markdown AST traversal. Update build pipeline,
templates, styles, and JS to support the new parser output. Refresh GitHub
stars data and update tests to match new parser behavior.

Co-Authored-By: Claude <noreply@anthropic.com>

website/fetch_github_stars.py

@@ -17,7 +17,7 @@ DATA_DIR = Path(__file__).parent / "data"
 CACHE_FILE = DATA_DIR / "github_stars.json"
 README_PATH = Path(__file__).parent.parent / "README.md"
 GRAPHQL_URL = "https://api.github.com/graphql"
-BATCH_SIZE = 100
+BATCH_SIZE = 50
 
 
 def extract_github_repos(text: str) -> set[str]:
@@ -50,7 +50,7 @@ def build_graphql_query(repos: list[str]) -> str:
             continue
         parts.append(
             f'repo_{i}: repository(owner: "{owner}", name: "{name}") '
-            f"{{ stargazerCount pushedAt owner {{ login }} }}"
+            f"{{ stargazerCount owner {{ login }} defaultBranchRef {{ target {{ ... on Commit {{ committedDate }} }} }} }}"
         )
     if not parts:
         return ""
@@ -67,10 +67,12 @@ def parse_graphql_response(
         node = data.get(f"repo_{i}")
         if node is None:
             continue
+        default_branch = node.get("defaultBranchRef") or {}
+        target = default_branch.get("target") or {}
         result[repo] = {
             "stars": node.get("stargazerCount", 0),
             "owner": node.get("owner", {}).get("login", ""),
-            "pushed_at": node.get("pushedAt", ""),
+            "last_commit_at": target.get("committedDate", ""),
         }
     return result
 
@@ -162,7 +164,7 @@ def main() -> None:
                     cache[repo] = {
                         "stars": results[repo]["stars"],
                         "owner": results[repo]["owner"],
-                        "pushed_at": results[repo]["pushed_at"],
+                        "last_commit_at": results[repo]["last_commit_at"],
                         "fetched_at": now_iso,
                     }
                     fetched_count += 1