Default the move dialog's promotion to the target kind, and link the new page

[JeroenDeDauw]

Follows-up to #1356

The promotion default follows the target kind. Moving a Subject onto a page that does not exist yet is how a Subject created in-flow on another page gets a page of its own: that page is about the Subject and has no main Subject to demote, so the "Make it the main subject" checkbox now arrives checked for it. An existing target page keeps its main Subject and leaves the box unchecked, as before. The default is applied whenever the target changes, so a manual tick or untick stands until the user picks a different page.

The success notification links the page. After the move, that page is where the user is headed, so the notification names it as a link to its Data tab instead of as plain text. The message is built with parseDom, which takes the link as a node and leaves the subject name beside it escaped; that needs mediawiki.jqueryMsg, now a declared module dependency rather than something the page happened to have loaded.

Considered, omitted

• Prefilling the page lookup with the Subject's label.
• An Undo action in the notification.
• Navigating to the target page automatically after the move.

Manual Browser Check

On a dev wiki, from the Data tab of Rijksmuseum, Move on an attendance Subject:

• typing a title no page has and picking "Use … as a new page" checks the box, with no demotion notice;
• picking an existing page instead unchecks it; picking the new-page option again re-checks it;
• confirming the move shows Moved "Rijksmuseum attendance 2020" to <a href="/w/index.php?title=Attendance_scratch_1&action=subjects">Attendance scratch 1</a>., and that link opens the new page's Data tab with the Subject as its main Subject.

_{AI-authored — Claude Code, Opus 5 (max); written spec from @JeroenDeDauw's Fable session, no revisions; diff not yet human-reviewed; vitest (1930 tests), build and lint run locally plus the browser check above; CI pending.}