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, 17 insertions, 0 deletions

diff --git a/.dispatch/wire.reference.md b/.dispatch/wire.reference.md
index 07dabc8..5379b11 100644
--- a/.dispatch/wire.reference.md
+++ b/.dispatch/wire.reference.md
@@ -6,6 +6,15 @@
 >
 > **Orchestrator:** SNAPSHOT of `[email protected]` (workspaces + computers + provider-retry + concurrency-`queued` status). Regenerate whenever `@dispatch/wire` changes.
 >
+> **2026-09-20 delta (workspace archiving — ADDITIVE to `[email protected]`, NO version bump):** `Workspace` gains a
+> required `archived: boolean` (defaults to `false` on creation; legacy rows normalize to `false`). An archived
+> workspace is HIDDEN from the home grid WITHOUT deleting its data (conversations/settings untouched) and can be
+> unarchived at any time. Toggled via dedicated `PUT`/`DELETE /workspaces/:id/archive` endpoints (no body; both
+> create-on-miss and return the updated `Workspace`; both reject `"default"` with 409). `GET /workspaces` takes an
+> optional `?archived=` query: `true` → archived only, `all` → every workspace, absent/other → non-archived only
+> (the home grid's default). `PUT /workspaces/:id` does NOT accept an `archived` field. Implemented in BOTH repos
+> of the `feature/archive-workspaces` worktree (see `backend-handoff.md`).
+>
 > **2026-08-25 delta (per-conversation model on ConversationMeta — ADDITIVE, no version bump):**
 > `ConversationMeta` gains an optional `model?: string` (`<credential>/<model>`, absENT = default
 > provider model). Surfaced on `GET /conversations` and the `conversation.open` WS broadcast so the
@@ -749,6 +758,14 @@ export interface Workspace {
 	 * Defaults to `false` on creation.
 	 */
 	readonly starred: boolean;
+	/**
+	 * Whether the workspace is archived by the user. Archived workspaces are
+	 * HIDDEN from the home grid (`GET /workspaces` excludes them by default;
+	 * `?archived=` opts back in) without deleting their data — the workspace,
+	 * its conversations, and its settings are untouched, and it can be
+	 * unarchived at any time. Defaults to `false` on creation.
+	 */
+	readonly archived: boolean;
 	/** Epoch-ms when the workspace was first created. */
 	readonly createdAt: number;
 	/** Epoch-ms of the most recent conversation activity in this workspace. */