Port feature from vitejs/devtools#526: render message actions as buttons on toast notifications

[antfubot]

Context

vitejs/devtools#526 ("feat(core): render message actions as buttons on toast notifications") by @dvcolomban rendered a message entry's actions (e.g. activate, which focuses a dock) as buttons on the toast itself, not just in the messages panel's detail view — and fixed a dock-id typo (devframes-plugin-messages with hyphens vs. the real mounted id devframes_plugin_messages with underscores, a leftover from the devframe 0.6 migration, vitejs/devtools#396) that silently broke "click a toast to open messages." It touched packages/core/src/client/webcomponents/components/display/ToastOverlay.vue in vitejs/devtools, which moved here as part of the v0.9 migration — the equivalent file today is packages/hub-ui/src/client/components/display/ToastOverlay.vue.

The PR also added a "Toast: With Action" demo button to playgrounds/core/src/pages/devtools.vue — that playground file still exists in vitejs/devtools unaffected, so that part of the PR can be re-added there directly rather than ported here.

Original PR description

Why

Toasts only ever showed the dismiss ✕ — an entry's own actions (e.g. the activate kind, which focuses a dock) only rendered in the messages panel's detail view, not on the toast that actually announced it.

What changed

• Renders entry.actions as buttons in the toast's own #actions slot, dispatching the same way the messages panel does: switchEntry(action.activate.dockId).
• Fixes a pre-existing bug found while manually testing this: switchEntry('devframes-plugin-messages') (hyphens) never matched the dock's real mounted id, devframes_plugin_messages (underscores, PLUGIN_ID in @devframes/plugin-messages's constants.ts) — a typo from the devframe 0.6 migration (#396) that's been silently breaking "click a toast to open messages" ever since.
• Adds a "Toast: With Action" button next to the existing Quick Actions in the playground's debug dashboard, so this (and the id fix) is easy to re-verify by hand later.

Diff: https://github.com/vitejs/devtools/pull/526/files

For agents picking this up

• Read the diff at feat(core): render message actions as buttons on toast notifications vitejs/devtools#526 for the toast #actions slot rendering and the switchEntry dispatch pattern.
• Port the ToastOverlay.vue change to packages/hub-ui/src/client/components/display/ToastOverlay.vue (+ its .stories.ts), adapting to whatever has shifted since the fork.
• Verify the devframes_plugin_messages (underscore) id typo fix is/isn't already correct in this repo's current @devframes/plugin-messages constants.ts and any switchEntry(...) call sites — the bug may be specific to how vitejs/devtools referenced the id, or it may still exist here too.
• The playground demo button doesn't need porting here — it can be re-added directly to vitejs/devtools's playgrounds/core/src/pages/devtools.vue, which is unaffected by the migration.
• Credit @dvcolomban as the original author: include a Co-authored-by: dvcolomban <...> trailer (look up their GitHub noreply email, or omit if unavailable) and mention them in the PR description.
• Link back to feat(core): render message actions as buttons on toast notifications vitejs/devtools#526 in the PR description.
• Close this issue when the port merges.