feat(workspaces): star toggle for concurrency priority

Backend (feature/workspace-star) shipped Workspace.starred: boolean (additive
to [email protected], no version bump) + PUT/DELETE /workspaces/:id/star endpoints
(no body; create-on-miss; return the updated Workspace). A starred workspace's
agents jump ahead of non-starred ones in the concurrency limiter queue
(oldest-agent-first within each group); takes effect immediately for
already-queued agents.

FE consumed:
- adapter/http.ts: star(id)/unstar(id) -> WorkspaceResult<Workspace>
  (PUT/DELETE /workspaces/:id/star, no body).
- logic/view-model.ts: pure sortWorkspaces (starred-first, then lastActivityAt
  desc, stable) + pure applyStarred (the optimistic apply/revert transform).
- store.svelte.ts: setStarred(id, starred) — optimistic flip with error revert;
  the list is now a $derived sorted view (starred bubble to top reactively);
  no full refresh on success (avoids flicker).
- ui/WorkspaceCard.svelte: star toggle button (filled gold when starred,
  outline when not; spinner in flight; aria-pressed/aria-label; tooltip notes
  concurrency priority).
- Re-mirrored .dispatch/wire.reference.md (starred + delta note).
- GLOSSARY.md: 'starred' term.

Tests (+27): http star/unstar (5), view-model sort+applyStarred (12), store
optimistic+revert+re-sort (6), WorkspaceCard star button (4).

Verification: typecheck 0/0, 1045 tests green, biome clean, build OK.
backend-handoff.md updated (workspace-star slice, no open backend asks).

1 files changed, 1 insertions, 1 deletions

diff --git a/src/features/workspaces/index.ts b/src/features/workspaces/index.ts
index 177e49b..dab1dec 100644
--- a/src/features/workspaces/index.ts
+++ b/src/features/workspaces/index.ts
@@ -8,7 +8,7 @@ export {
   WORKSPACE_SLUG_RE,
   workspacePath,
 } from "./logic/route";
-export { pageTitle, relativeTime } from "./logic/view-model";
+export { applyStarred, pageTitle, relativeTime, sortWorkspaces } from "./logic/view-model";
 export type { WorkspaceStore } from "./store.svelte";
 export { createWorkspaceStore } from "./store.svelte";
 export { default as WorkspaceCard } from "./ui/WorkspaceCard.svelte";