fix: search Session tab content in New Tab

[WangEn]

Summary

• make Extension New Tab Session results searchable by Session name, source device, tab title, and partial tab URL
• show the matching tab title and URL in the Session result subtitle when an internal tab caused the match
• add Chromium New Tab UX regression coverage using a Chinese tab title and mail.bist.edu.cn URL partials
• release the Extension as 1.5.2 so the fix is actually packaged and users on 1.5.1 receive an update

Root cause

The New Tab sessionResult() only passed session.name and N tabs · sourceDevice into searchScore(). Session item titles and URLs were never part of the searchable text, so queries such as 学生电子, mail.bist, or bist.edu.cn/mail fell through to the default web search even when those values existed inside a cached Session.

Validation

• 学生电子 returns the Session containing the matching Chinese tab title
• mail.bist and bist.edu.cn/mail return the same Session via partial URL matching
• existing Session-name search and Enter-to-restore behavior remain green
• version alignment reports 1.5.2 across package / manifest / Web distribution
• CI #217: verify / Chromium / New Tab / Firefox all green
• after merge, verify Extension Release creates v1.5.2 and all four ZIP assets