feat(link): 連結一律寫成 [文字](絕對網址)，寫入前先驗證連得到

取消 [[頁名]] 與 [[顯示文字|頁名]] 兩種同 wiki 寫法，不再分「同存取庫」與
「跨存取庫」兩條規則。那種寫法只在自己那個 wiki 內解析，寫錯不報錯，畫面上
看起來像普通文字或死連結，巡不到也修不了。

連結寫進頁面前先過 jsc-gitea 的 link-check.sh，結束碼 0 才寫。驗證一律走 API，
不看網頁狀態碼：私有存取庫的網頁網址對未登入請求一律回 404，拿狀態碼判會把
好連結判成壞的。認證失敗回 7，與死連結的 1 分開，免得金鑰一過期就把還在的頁
整批判死。

skills/html-export/SKILL.md

@@ -17,7 +17,7 @@ The link is the only input. The output is one file that opens anywhere, with no
    - **Track C — destination.** Ask per the `jsc-ask:ask` rules where the file goes, proposing `./.jsc/html/{page-or-issue}.html`. State the impact scope: a path inside a repository gets committed unless it is ignored.
 
    Completion condition: the markdown and the document title are in hand, exactly one kind key is chosen with the reason that produced it, the layout, style and source are reported, and the user has confirmed one output path.
-4. **Prepare the markdown — this step MUST run as a sub agent.** Convert `[[display|page]]` wiki links to absolute URLs from `wiki-url`; the renderer does not resolve them, so they would ship as literal brackets. Strip personal data — an exported file travels further than the page it came from. Leave everything else exactly as written; this step never rewrites the content. Completion condition: no `[[...]]` remains, and the diff against the source is limited to link conversion and personal-data removal.
+4. **Prepare the markdown — this step MUST run as a sub agent.** Links are written as `[text](absolute URL)`, so pages that follow the current rule need no conversion. An older page can still carry a wiki-internal link: turn it into an absolute URL from `wiki-url`, because the renderer does not resolve it and it would ship as literal brackets. Strip personal data — an exported file travels further than the page it came from. Leave everything else exactly as written; this step never rewrites the content. Completion condition: every link in the file is `[text](absolute URL)`, and the diff against the source is limited to link conversion and personal-data removal.
 5. Render: `tools/html-render.sh --markdown {file} --title {title} --layout {layout} --style {style} --source-url {absolute URL} --out {path}`. Route every exit code: 0 → the path it printed is the finished file; 1 → Gitea's renderer or the write failed, so report it and stop, with no half-rendered file left behind; 2 → a usage error or a missing markdown file, so fix the arguments and call again; 4 → the layout or style template file is gone, so report which pair was asked for and send the user to `jsc-gitea:html-style` rather than editing the configuration by hand. Completion condition: the file exists, and the report names its path, the layout, the style and where that pair came from.
 
 ## Rules