feat(workspaces): archive option + archived-workspaces view

Consume the backend's archive contract (feature/archive-workspaces):

- adapter/http: archive(id)/unarchive(id) (PUT/DELETE /workspaces/:id/archive);
  list(archived?) passes the ?archived= query
- logic/view-model: pure applyArchived(list, id, archived)
- store.svelte: setArchived(id, archived) (optimistic + revert-on-error +
  reconciling refresh); archivedList + refreshArchived() for the archived view
- ui/TileActionBar: new Archive action (the right-click→select action bar)
- ui/HomeHeader: new Archived button opens the archived view
- ui/ArchivedWorkspaces (new): modal listing archived workspaces with
  Unarchive + View (navigates to /<id>)
- ui/WorkspacesHome: wire the Archive action + the Archived modal
- .dispatch/wire.reference.md + backend-handoff.md: record the contract delta

1 files changed, 4 insertions, 0 deletions

diff --git a/src/features/workspaces/ui/TileActionBar.svelte b/src/features/workspaces/ui/TileActionBar.svelte
index 0d8bef5..ffb8f1d 100644
--- a/src/features/workspaces/ui/TileActionBar.svelte
+++ b/src/features/workspaces/ui/TileActionBar.svelte
@@ -11,6 +11,7 @@
     onToggleStar,
     onDetails,
     onPlugins,
+    onArchive,
     onDelete,
     onClose,
   }: {
@@ -24,6 +25,8 @@
     /** The details flyout (default cwd + default computer). */
     onDetails: () => void;
     onPlugins: () => void;
+    /** Archive the workspace (hide from the home grid; reversible). */
+    onArchive: () => void;
     onDelete: () => void;
     onClose: () => void;
   } = $props();
@@ -53,6 +56,7 @@
     {#if withPlugins}
       <button type="button" class="btn btn-ghost btn-sm" onclick={onPlugins}>Plugins</button>
     {/if}
+    <button type="button" class="btn btn-ghost btn-sm" onclick={onArchive}>Archive</button>
     <button
       type="button"
       class="btn btn-ghost btn-sm text-error"