feat: configurable status lines for CLI footer (#904)

Co-authored-by: Letta <noreply@letta.com>

src/tests/cli/statusline-help.test.ts

@@ -0,0 +1,34 @@
+import { describe, expect, test } from "bun:test";
+import { formatStatusLineHelp } from "../../cli/helpers/statusLineHelp";
+
+describe("statusLineHelp", () => {
+  test("includes configuration and input sections", () => {
+    const output = formatStatusLineHelp();
+
+    expect(output).toContain("/statusline help");
+    expect(output).toContain("CONFIGURATION");
+    expect(output).toContain("INPUT (via JSON stdin)");
+    expect(output).toContain("model.display_name");
+    expect(output).toContain("context_window.used_percentage");
+  });
+
+  test("lists all fields without section separation", () => {
+    const output = formatStatusLineHelp();
+
+    // Native and derived fields both present in a single list
+    expect(output).toContain("cwd");
+    expect(output).toContain("session_id");
+    expect(output).toContain("context_window.remaining_percentage");
+    expect(output).toContain("exceeds_200k_tokens");
+
+    // No native/derived subheadings
+    expect(output).not.toContain("\nnative\n");
+    expect(output).not.toContain("\nderived\n");
+  });
+
+  test("does not include effective config section", () => {
+    const output = formatStatusLineHelp();
+
+    expect(output).not.toContain("Effective config:");
+  });
+});