fix: prefer article titles in webfetch

[code-yeongyu]

Summary

Fixes a Tistory title regression where a blog-level header <h1> could be chosen before the real article title. The reader-mode fallback now scans title selectors in preferred order, so .tit_post and common article title classes win over generic h1 chrome.

Changes

• Replace DOM-order comma selector title lookup with an ordered TITLE_SELECTORS scan.
• Apply the same preferred-title lookup to explicit article extraction and Readability fallback.
• Add markdown and text regressions for a Tistory page where site chrome appears before the article title.

QA / Evidence

• npm test: 4 files passed, 37 tests passed.
• npm run check: tsgo --noEmit and biome check . passed.

Risks

• Low. The fallback still uses the document/Readability title when no preferred selector has text, and the new tests cover the exact chrome-before-article failure mode.

Secret safety

• No logs, credentials, cookies, or auth-bearing output included.

---

Summary by cubic

Prefer article titles in webfetch so site-level h1 (e.g., Tistory blog headers) no longer override the real article title. Markdown and text outputs now pick .tit_post and other common article title classes before generic h1 or the document title.

• Bug Fixes
  • Replaced DOM-order title query with ordered TITLE_SELECTORS and selectPreferredTitle().
  • Applied the same title preference to explicit article extraction and Readability fallback.
  • Added markdown/text tests to cover Tistory pages and prevent chrome-over-article regressions.

^{Written for commit e2fab0c. Summary will update on new commits.}

Post-merge Audit Addendum

• Failing-first title-priority proof was captured after merge by applying only the new title tests to the previous implementation commit.
  • External RED artifact: /Users/yeongyu/local-workspaces/senpi-webfetch-tistory-worktree/local-ignore/qa-evidence/20260626-webfetch-title-selector/pi-webfetch-title-red.txt
  • Failure proved the old external implementation selected # 블로그 이름 instead of # 티스토리 본문을 읽어야 합니다.
• The matching GREEN proof remains the PR validation: npm test passed 37 tests and CI passed on Ubuntu/macOS Node 20/22.