fix(AppShell): wire up <bold/> control hint for labels

[alexwarren]

Summary

• Part of Editor: several v5 .aslx control hints not wired through to AppShell (freetext, min/max/increment, nullable, width, ...) #2116.
• <bold/> was fully dead (2 uses: an exit's "to unlock this exit..." warning-style note in CoreEditorExit.aslx:50, and a container's disabled-feature notice in CoreEditorObjectContainer.aslx:20) - a "label" control's caption always rendered in normal weight regardless of the tag.
• Threads ctrl.GetBool("bold") through ToControlInfo into a conditional font-semibold class on both label rendering branches (plain text and href link) in PropertyEditor.svelte.

Test plan

• dotnet build --configuration Release
• dotnet test --configuration Release (all passing)
• npm run check / npm run lint in src/AppShell (clean)
• node tests/e2e/find-affected-tests.mjs + ran verify-appshell-exits-editor against a local dev server - passes.
• Manual check in-browser: checked an exit's "Locked" box (with no name set) to surface the "To unlock this exit during the game or to change its visibility using a script, you must give it a name below." label, and confirmed via computed style that it now renders with font-weight: 600 (previously 400).

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