WebUI dependency modernisation (Vue 2.7 -> 3, drop element-ui / golden-layout)

[Powback]

Tracking issue so this isn't lost. Not urgent — nothing here is user-visible, and a big-bang upgrade is actively risky under Gameface. Recommendation at the bottom is the incremental path.

Current state

The WebUI is on Vue 2.7.16 (the final 2.x release) plus a stack of packages that have no Vue 3 version:

Package	Version	Vue 3 status
element-ui	2.15.9	Vue 2 only -> element-plus (different API). ~10 component types in use (el-menu, el-input, el-checkbox, …)
vue-class-component	7.2.6	No Vue 3 support
vue-property-decorator	9.1.2	No Vue 3 support
@vue/composition-api	1.7.2	Backport shim, removed in Vue 3 (imported by 26 components)
vuex	3.6.2	-> Vuex 4 / Pinia
vue-router	3.5.2	-> vue-router 4
vue-virtual-scroller	1.0.10	Vue 2 only
vue-promised	2.2.0	Vue 2 only
golden-layout / vue-golden-layout	1.5.9 / 2.1.1	Already unused — the Gameface port replaced the docking with a static flexbox layout, but the dependency is still declared

Component split on the Gameface branch: 26 of 48 .vue files already use defineComponent; 15 are still class components (the big ones: Inspector, Hierarchy, History, Explorer, Viewport, Toolbar, Console…).

development already started this — 3a9fb935 chore(vue): migrate away from class components — but that branch has diverged from Gameface and the two migrations would conflict in exactly those 15 files.

Why this is not a simple upgrade

The WebUI does not run in a browser — it runs in Gameface/Cohtml, which is where most of our UI bugs come from (no CSS Grid, no :not()/:last-child, elements have no .click(), scrollIntoView unreliable, native checkboxes don't toggle). Vue 3 changes the renderer and swaps reactivity to Proxies; none of that has been validated against Cohtml, and breakage would only surface at runtime, in-game.

The upgrade delivers zero user-visible features. It's pure maintenance.

element-ui is a liability regardless of Vue version

el-checkbox does not toggle in Cohtml — it was already replaced with a plain clickable div in the bool control. So the useful direction is removing element-ui, not porting it to element-plus.

Recommended incremental path (low risk, any order)

1. Drop golden-layout + vue-golden-layout — already unused; free win.
2. Replace remaining element-ui usages with Gameface-safe primitives, as they're touched.
3. Convert the last 15 class components to defineComponent opportunistically.

That leaves the codebase Vue-3-ready without a big-bang, and matches the direction development was already heading. Only after 1-3 does an actual Vue 3 bump become a contained piece of work.

Context: filed while working on branch live-ebx; a legacy branch was created at development's tip (1a37ff76) as a restore point.