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
(dfe1711) imported features/settings from app/App.svelte but never committed
the feature, so only the full working tree was green.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/features/settings/index.ts b/src/features/settings/index.ts
new file mode 100644
index 0000000..69e7cd0
--- /dev/null
+++ b/src/features/settings/index.ts
@@ -0,0 +1,9 @@
+export type { ChatLimitParse, ChatLimitSaveResult, SaveChatLimit } from "./logic/view-model";
+export { chatLimitChanged, parseChatLimit } from "./logic/view-model";
+export { default as ChatLimitField } from "./ui/ChatLimitField.svelte";
+
+/** Public module manifest — aggregated by the shell's "Loaded Modules" view. */
+export const manifest = {
+	name: "settings",
+	description: "FE-local settings (chat limit)",
+} as const;