feat(FN-3046): add fn binary panel and standalone CLI entrypoint

This merge introduces a standalone CLI binary mode ("droid") with a new dashboard panel for binary management, adds a todo planning entrypoint with peer exchange shutdown, and includes documentation updates for the CLI reference and standalone deployment. Key additions span the core database layer,

Fusion-Task-Id: FN-3046

packages/core/src/__tests__/fn-binary.test.ts

@@ -0,0 +1,37 @@
+import { describe, it, expect } from "vitest";
+import {
+  detectFnBinary,
+  FN_INSTALL_CURL,
+  FN_INSTALL_NPM,
+  FN_NPM_PACKAGE,
+  FN_NPX_INVOCATION,
+} from "../fn-binary.js";
+
+describe("fn-binary constants", () => {
+  it("uses runfusion.ai as the canonical npm package", () => {
+    expect(FN_NPM_PACKAGE).toBe("runfusion.ai");
+    expect(FN_INSTALL_NPM).toBe("npm install -g runfusion.ai");
+    expect(FN_NPX_INVOCATION).toBe("npx -y runfusion.ai");
+  });
+
+  it("exposes the curl one-line installer", () => {
+    expect(FN_INSTALL_CURL).toBe("curl -fsSL https://runfusion.ai/install.sh | sh");
+  });
+});
+
+describe("detectFnBinary", () => {
+  it("never throws and always returns a usable invocation", async () => {
+    // We don't assert installed/missing — the host running CI may or may not
+    // have `fn` on PATH. The contract is: result is well-formed and
+    // `invocation` is a string the caller can prepend to a command.
+    const result = await detectFnBinary();
+    expect(typeof result.installed).toBe("boolean");
+    expect(typeof result.invocation).toBe("string");
+    expect(result.invocation.length).toBeGreaterThan(0);
+    if (!result.installed) {
+      expect(result.invocation).toBe(FN_NPX_INVOCATION);
+    } else {
+      expect(["fn", "fusion"]).toContain(result.binary);
+    }
+  });
+});