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, 61 insertions, 0 deletions

diff --git a/src/features/settings/logic/view-model.test.ts b/src/features/settings/logic/view-model.test.ts
new file mode 100644
index 0000000..65fcae9
--- /dev/null
+++ b/src/features/settings/logic/view-model.test.ts
@@ -0,0 +1,61 @@
+import { describe, expect, it } from "vitest";
+import { MAX_CHAT_LIMIT, MIN_CHAT_LIMIT } from "../../../core/chunks";
+import { chatLimitChanged, parseChatLimit } from "./view-model";
+
+describe("parseChatLimit", () => {
+	it("parses a plain integer", () => {
+		expect(parseChatLimit("256")).toEqual({ ok: true, value: 256 });
+		expect(parseChatLimit("100")).toEqual({ ok: true, value: 100 });
+	});
+
+	it("trims surrounding whitespace", () => {
+		expect(parseChatLimit("  50  ")).toEqual({ ok: true, value: 50 });
+	});
+
+	it("floors a decimal", () => {
+		expect(parseChatLimit("100.9")).toEqual({ ok: true, value: 100 });
+	});
+
+	it("clamps below the floor to MIN_CHAT_LIMIT", () => {
+		expect(parseChatLimit("0")).toEqual({ ok: true, value: MIN_CHAT_LIMIT });
+		expect(parseChatLimit("-5")).toEqual({ ok: true, value: MIN_CHAT_LIMIT });
+		expect(parseChatLimit("5")).toEqual({ ok: true, value: MIN_CHAT_LIMIT });
+	});
+
+	it("clamps above the ceiling to MAX_CHAT_LIMIT", () => {
+		expect(parseChatLimit("99999999")).toEqual({ ok: true, value: MAX_CHAT_LIMIT });
+	});
+
+	it("rejects an empty string", () => {
+		expect(parseChatLimit("")).toEqual({ ok: false, error: expect.any(String) });
+		expect(parseChatLimit("   ")).toEqual({ ok: false, error: expect.any(String) });
+	});
+
+	it("rejects non-numeric input", () => {
+		expect(parseChatLimit("abc")).toEqual({ ok: false, error: expect.any(String) });
+		expect(parseChatLimit("twelve")).toEqual({ ok: false, error: expect.any(String) });
+	});
+});
+
+describe("chatLimitChanged", () => {
+	it("is false when the typed value normalizes to the current limit", () => {
+		expect(chatLimitChanged("256", 256)).toBe(false);
+	});
+
+	it("is true when the typed value differs", () => {
+		expect(chatLimitChanged("100", 256)).toBe(true);
+		expect(chatLimitChanged("256", 100)).toBe(true);
+	});
+
+	it("is false for empty / invalid input (nothing submittable)", () => {
+		expect(chatLimitChanged("", 256)).toBe(false);
+		expect(chatLimitChanged("abc", 256)).toBe(false);
+	});
+
+	it("is false when the typed value clamps to the current limit", () => {
+		// 5 clamps to MIN (10); current is already 10 → no change.
+		expect(chatLimitChanged("5", MIN_CHAT_LIMIT)).toBe(false);
+		// A huge value clamps to MAX; current is already MAX → no change.
+		expect(chatLimitChanged("99999999", MAX_CHAT_LIMIT)).toBe(false);
+	});
+});