feat: use sudo for tailscale configuration commands

To avoid permission denied errors when modifying Tailscale configuration (serve/funnel),
we now prepend `sudo -n` to these commands. This ensures that if the user has appropriate
sudo privileges (specifically passwordless for these commands or generally), the operation
succeeds. If sudo fails (e.g. requires password non-interactively), it will throw an error
which is caught and logged as a warning, preserving existing behavior but attempting to escalate privileges first.

- Updated `ensureFunnel` to use `sudo -n` for the enabling step.
- Updated `enableTailscaleServe`, `disableTailscaleServe`, `enableTailscaleFunnel`, `disableTailscaleFunnel` to use `sudo -n`.
- Added tests in `src/infra/tailscale.test.ts` to verify `sudo` usage.

src/infra/tailscale.test.ts

@@ -1,6 +1,15 @@
 import { describe, expect, it, vi } from "vitest";
 
-import { ensureGoInstalled, ensureTailscaledInstalled, getTailnetHostname } from "./tailscale.js";
+import {
+  ensureGoInstalled,
+  ensureTailscaledInstalled,
+  getTailnetHostname,
+  enableTailscaleServe,
+  disableTailscaleServe,
+  enableTailscaleFunnel,
+  disableTailscaleFunnel,
+  ensureFunnel
+} from "./tailscale.js";
 
 describe("tailscale helpers", () => {
   it("parses DNS name from tailscale status", async () => {
@@ -48,4 +57,75 @@ describe("tailscale helpers", () => {
     await ensureTailscaledInstalled(exec as never, prompt, runtime);
     expect(exec).toHaveBeenCalledWith("brew", ["install", "tailscale"]);
   });
+
+  it("enableTailscaleServe uses sudo", async () => {
+    const exec = vi.fn().mockResolvedValue({ stdout: "" });
+    await enableTailscaleServe(3000, exec as never);
+    expect(exec).toHaveBeenCalledWith(
+      "sudo",
+      expect.arrayContaining(["-n", "tailscale", "serve", "--bg", "--yes", "3000"]),
+      expect.any(Object)
+    );
+  });
+
+  it("disableTailscaleServe uses sudo", async () => {
+    const exec = vi.fn().mockResolvedValue({ stdout: "" });
+    await disableTailscaleServe(exec as never);
+    expect(exec).toHaveBeenCalledWith(
+      "sudo",
+      expect.arrayContaining(["-n", "tailscale", "serve", "reset"]),
+      expect.any(Object)
+    );
+  });
+
+  it("enableTailscaleFunnel uses sudo", async () => {
+    const exec = vi.fn().mockResolvedValue({ stdout: "" });
+    await enableTailscaleFunnel(4000, exec as never);
+    expect(exec).toHaveBeenCalledWith(
+      "sudo",
+      expect.arrayContaining(["-n", "tailscale", "funnel", "--bg", "--yes", "4000"]),
+      expect.any(Object)
+    );
+  });
+
+  it("disableTailscaleFunnel uses sudo", async () => {
+    const exec = vi.fn().mockResolvedValue({ stdout: "" });
+    await disableTailscaleFunnel(exec as never);
+    expect(exec).toHaveBeenCalledWith(
+      "sudo",
+      expect.arrayContaining(["-n", "tailscale", "funnel", "reset"]),
+      expect.any(Object)
+    );
+  });
+
+  it("ensureFunnel uses sudo for enabling", async () => {
+    // Mock exec: first call is status (not sudo), second call is enable (sudo)
+    const exec = vi.fn()
+      .mockResolvedValueOnce({ stdout: JSON.stringify({ BackendState: "Running" }) }) // status
+      .mockResolvedValueOnce({ stdout: "" }); // enable
+
+    const runtime = {
+      error: vi.fn(),
+      log: vi.fn(),
+      exit: vi.fn() as unknown as (code: number) => never,
+    };
+    const prompt = vi.fn();
+
+    await ensureFunnel(8080, exec as never, runtime, prompt);
+
+    // First call: check status (no sudo)
+    expect(exec).toHaveBeenNthCalledWith(
+      1,
+      "tailscale",
+      expect.arrayContaining(["funnel", "status", "--json"])
+    );
+
+    // Second call: enable (sudo)
+    expect(exec).toHaveBeenNthCalledWith(
+      2,
+      "sudo",
+      expect.arrayContaining(["-n", "tailscale", "funnel", "--yes", "--bg", "8080"]),
+      expect.any(Object)
+    );
+  });
 });

src/infra/tailscale.ts

@@ -237,7 +237,7 @@ export async function ensureFunnel(
     }
 
     logVerbose(`Enabling funnel on port ${port}…`);
-    const { stdout } = await exec(tailscaleBin, ["funnel", "--yes", "--bg", `${port}`], {
+    const { stdout } = await exec("sudo", ["-n", tailscaleBin, "funnel", "--yes", "--bg", `${port}`], {
       maxBuffer: 200_000,
       timeoutMs: 15_000,
     });
@@ -288,7 +288,7 @@ export async function ensureFunnel(
 
 export async function enableTailscaleServe(port: number, exec: typeof runExec = runExec) {
   const tailscaleBin = await getTailscaleBinary();
-  await exec(tailscaleBin, ["serve", "--bg", "--yes", `${port}`], {
+  await exec("sudo", ["-n", tailscaleBin, "serve", "--bg", "--yes", `${port}`], {
     maxBuffer: 200_000,
     timeoutMs: 15_000,
   });
@@ -296,7 +296,7 @@ export async function enableTailscaleServe(port: number, exec: typeof runExec =
 
 export async function disableTailscaleServe(exec: typeof runExec = runExec) {
   const tailscaleBin = await getTailscaleBinary();
-  await exec(tailscaleBin, ["serve", "reset"], {
+  await exec("sudo", ["-n", tailscaleBin, "serve", "reset"], {
     maxBuffer: 200_000,
     timeoutMs: 15_000,
   });
@@ -304,7 +304,7 @@ export async function disableTailscaleServe(exec: typeof runExec = runExec) {
 
 export async function enableTailscaleFunnel(port: number, exec: typeof runExec = runExec) {
   const tailscaleBin = await getTailscaleBinary();
-  await exec(tailscaleBin, ["funnel", "--bg", "--yes", `${port}`], {
+  await exec("sudo", ["-n", tailscaleBin, "funnel", "--bg", "--yes", `${port}`], {
     maxBuffer: 200_000,
     timeoutMs: 15_000,
   });
@@ -312,7 +312,7 @@ export async function enableTailscaleFunnel(port: number, exec: typeof runExec =
 
 export async function disableTailscaleFunnel(exec: typeof runExec = runExec) {
   const tailscaleBin = await getTailscaleBinary();
-  await exec(tailscaleBin, ["funnel", "reset"], {
+  await exec("sudo", ["-n", tailscaleBin, "funnel", "reset"], {
     maxBuffer: 200_000,
     timeoutMs: 15_000,
   });