feat(baoyu-url-to-markdown): add URL-specific parser layer for X/Twitter and archive.ph

- New parsers/ module with pluggable rule system for site-specific HTML extraction
- X status parser: extract tweet text, media, quotes, author from data-testid elements
- X article parser: extract long-form article content with inline media
- archive.ph parser: restore original URL and prefer #CONTENT container
- Improved slug generation with stop words and content-aware slugs
- Output path uses subdirectory structure (domain/slug/slug.md)
- Fix: preserve anchor elements containing media in legacy converter
- Fix: smarter title deduplication in markdown document builder

skills/baoyu-url-to-markdown/scripts/parsers/index.ts

@@ -0,0 +1,47 @@
+import {
+  isMarkdownUsable,
+  normalizeMarkdown,
+  parseDocument,
+  type ConversionResult,
+  type PageMetadata,
+} from "../markdown-conversion-shared.js";
+import { URL_RULE_PARSERS } from "./rules/index.js";
+import type { UrlRuleParserContext } from "./types.js";
+
+export type { UrlRuleParser, UrlRuleParserContext } from "./types.js";
+
+export function tryUrlRuleParsers(
+  html: string,
+  url: string,
+  baseMetadata: PageMetadata
+): ConversionResult | null {
+  const document = parseDocument(html);
+  const context: UrlRuleParserContext = {
+    html,
+    url,
+    document,
+    baseMetadata,
+  };
+
+  for (const parser of URL_RULE_PARSERS) {
+    if (!parser.supports(context)) continue;
+
+    try {
+      const result = parser.parse(context);
+      if (!result) continue;
+
+      const markdown = normalizeMarkdown(result.markdown);
+      if (!isMarkdownUsable(markdown, html)) continue;
+
+      return {
+        ...result,
+        markdown,
+      };
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error);
+      console.warn(`[url-to-markdown] parser ${parser.id} failed: ${message}`);
+    }
+  }
+
+  return null;
+}