feat: Add cnki-patent-search and cnki-patent-detail skills

[cylixlee]

Add two new skills for searching and reading patents on CNKI (中国知网), following the same patterns as the existing paper skills (cnki-search / cnki-paper-detail).

New Skills

Skill	Description
cnki-patent-search	Keyword search for Chinese patents. Navigates to kns.cnki.net/kns8s/search?classid=VUDIXAIY, fills the search form, and extracts structured patent data from result rows.
cnki-patent-detail	Extract full patent metadata from a patent detail page: title, patent type, application/grant numbers and dates, applicant, inventors, address, IPC classification, claims, abstract, legal status, and more.

Design

• 2 tool calls per skill (navigate_page + evaluate_script), matching the existing skill architecture.
• Same captcha detection logic inherited from the paper skills.
• No new dependencies, no additional scripts.
• All DOM selectors verified against live CNKI patent pages.

Differences from Paper Skills

Aspect	Paper	Patent
Search URL	/kns8s/search	/kns8s/search?classid=VUDIXAIY
Result columns	td.author / td.source / td.quote / td.download	td.inventor / td.applicant / 2× td.date (no citations/downloads)
Detail page DOM	.brief h3.author, p.keywords, .abstract-text	.brief div.row > span.rowtit + p.funds (generic row layout, no semantic classes)
Keywords	Present	Not available on patent pages
Extra fields	—	IPC codes, claims, legal status, agency/agent