Open the import row in the shell, not in a browser tab

[AllTerrainDeveloper]

Reported from the desktop: clicking Import forms in the dock's hover submenu opened the page in a new browser tab instead of a window in the shell.

Why

I gave the row a url and left the opening to the shell, on the strength of its type doc — "url stays the fallback for anything that can express itself as one". That sentence is about menu tiles. The constellation's runRow() reads:

if ( sub.onSelect ) { sub.onSelect(); return; }
if ( item.menuItem ) { openSubmenuItem( deps, item.menuItem, sub ); return; }  // ← routes into a window
if ( sub.url ) {
	// An action menu has no window routing behind it, so a row
	// that is only a URL is a link out — …
	window.open( sub.url, '_blank', 'noopener,noreferrer' );
}

Ours is a system tile registered with registerSystemTile(), so there is no menuItem behind it and no routing to fall into. A URL-only row is, by that code's own reasoning, a link out — correct for the row it was written for ("View site"), exactly wrong for an admin page.

The fix

The row now carries an onSelect that opens the page itself, through wp.os.windowManager.open() — the same call the shell makes when it routes an admin URL of its own:

void manager.open( { id, url, title, icon: 'dashicons-download' } );

• Stable id (allterrain-forms-import), so a second click focuses the open window instead of stacking another; singleton reuse is the manager's documented behaviour for a window without multi.
• windowId declared on the row, so the constellation lists it under "Open windows" when it is open rather than offering to open a second copy.
• url kept in step with what the callback opens — the shell now reads the callback, but the URL is what the row means, and it is the value the fallback uses.
• No-shell fallback navigates rather than calling window.open: a pop-up the browser is entitled to block is not a fallback.

Verified on the desktop, with instrumentation this time

I saw this new tab in my own testing of the previous PR and waved it off as an automation artifact. It wasn't, so this round is measured rather than eyeballed — window.open was patched with a counter before clicking:

	before fix	after fix
window.open calls	1	0
browser tabs	2	1
allterrain-forms-import windows in the shell	0	1
after clicking the row a second time	—	still 1 (focused, not duplicated)

The window renders the import page correctly, listing the seeded Contact Form 7 form.

Tests: 2 new vitest cases pinning the behaviour — the row's onSelect calls windowManager.open with the right id, url and title, and the no-shell path navigates instead. 248 vitest green, tsc clean.

🤖 Generated with Claude Code

https://claude.ai/code/session_0119U4sRRWGcTQdwYreTwpAp