feat(mapgen-studio): icon-only autoplay and run-in-game buttons, add Explore placeholder

[mateicanavra]

The GameConsole command buttons (Autoplay and Run in Game) are converted to icon-only, and a new Explore button is added between them.

Autoplay now renders FastForward (start), Square (stop), or a LoaderCircle spinner when a start/stop request is in flight. The start/stop/in-flight wording that was previously on the button label moves entirely into aria-label, title, and the Tooltip.

Run in Game now renders SquareArrowOutUpRight instead of MonitorPlay with a text label. The dynamic action label ("Run in Game", "Retry Run", "Restart Civ & Run") is preserved as the first line of the button's aria-label, title, and Tooltip so recovery states remain discoverable.

Explore is a new icon-only Binoculars button placed between Autoplay and Run in Game. It is wired behind an optional onExplore prop and renders disabled with an accessible name announcing that tile-visibility control is not yet available until a handler is provided.

A test is added to assert that the Explore button renders in its disabled placeholder state when no handler is wired.

[github-actions]

Railway preview (MapGen Studio): not provisioned for this PR.

Policy (Graphite stacks): previews are created only for the top-of-stack PR by default.

• To force a preview for this PR: add label railway-preview
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Debug: {"isClosed":false,"isFork":false,"suppress":false,"force":false,"isTopOfStack":false,"hasToken":true,"draft":false}

[mateicanavra]

Merge activity

• Jun 12, 8:50 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Jun 12, 9:49 PM UTC: Graphite rebased this pull request as part of a merge.
• Jun 12, 9:49 PM UTC: @mateicanavra merged this pull request with Graphite.