feat: workspaces shell + cwd-lsp rename + mcp/settings/system-prompt features + app wiring

- workspaces: URL-driven conversation grouping (home listing at /, routing,
  store, http adapter, WorkspaceCard) wired into the App.svelte shell
- rename features/workspace -> features/cwd-lsp (the cwd/lsp status feature)
- new features: mcp (status view), settings (chat-limit field), system-prompt
  (prompt builder), all rendered via the generic surface host
- chat: store + ChatView updates
- tabs: tabs-store updates
- app wiring: ErrorModal (full-screen error surface), app/App.svelte + store.svelte

This commit makes HEAD typecheck clean for the first time: the prior HEAD
(c95cc77) imported features/settings from app/App.svelte but never committed
the feature, so only the full working tree was green.

1 files changed, 41 insertions, 0 deletions

diff --git a/src/features/workspaces/logic/view-model.ts b/src/features/workspaces/logic/view-model.ts
new file mode 100644
index 0000000..e904514
--- /dev/null
+++ b/src/features/workspaces/logic/view-model.ts
@@ -0,0 +1,41 @@
+/**
+ * Pure view-model helpers for the workspaces feature — zero DOM, zero effects.
+ */
+
+import type { WorkspaceEntry } from "@dispatch/wire";
+import type { Route } from "./route";
+
+/**
+ * The browser tab / page (`document.title`) text for a route. The home route
+ * (`/`) is "Dispatch"; a workspace route (`/<id>`) is "Dispatch: {title}",
+ * using the workspace's display title and falling back to the URL slug (`id`)
+ * until the workspace list has loaded it — the backend defaults a workspace's
+ * title to its id, so the slug is the correct transient value. Pure: route +
+ * workspaces in, string out.
+ */
+export function pageTitle(route: Route, workspaces: readonly WorkspaceEntry[]): string {
+	if (route.kind === "home") return "Dispatch";
+	const ws = workspaces.find((w) => w.id === route.id);
+	return `Dispatch: ${ws?.title ?? route.id}`;
+}
+
+/**
+ * Format an epoch-ms timestamp as a short relative string ("now", "3m", "2h",
+ * "5d", or a date). Pure: `now` + `then` in, string out. Future timestamps
+ * (a workspace just created) read as "now".
+ */
+export function relativeTime(then: number, now: number): string {
+	const diff = now - then;
+	if (diff < 60_000) return "now";
+	const mins = Math.floor(diff / 60_000);
+	if (mins < 60) return `${mins}m`;
+	const hours = Math.floor(mins / 60);
+	if (hours < 24) return `${hours}h`;
+	const days = Math.floor(hours / 24);
+	if (days < 7) return `${days}d`;
+	// Beyond a week: a short date (MM/DD). Uses UTC parts for determinism in tests.
+	const d = new Date(then);
+	const month = String(d.getUTCMonth() + 1).padStart(2, "0");
+	const day = String(d.getUTCDate()).padStart(2, "0");
+	return `${month}/${day}`;
+}