fix: make browser daemon setup work on Windows (#7) (#12)

The Unix socket daemon introduced in v0.6.0 made several POSIX-only
assumptions that break setup on Windows:

- protocol.ts hardcoded a Unix socket path (/tmp/pi-browser-daemon.sock).
  Node IPC on Windows requires a named pipe (\\.\pipe\<name>); a /tmp
  path is not a valid net listen/connect target there.
- spawn.ts spawned the bare tsx binary / `npx` and probed the non-Windows
  .bin/tsx shim. On Windows npm binaries are .cmd shims that must run via a
  shell, and spawning them directly fails with EINVAL / ENOENT.
- isDaemonRunning() pre-checked the socket with fs.access(), which always
  fails for a named pipe and would report a live daemon as dead.
- stale-socket unlink() would throw on a named pipe path.

Changes:
- DAEMON_SOCKET_PATH is now platform-aware: named pipe on win32, Unix
  socket elsewhere.
- spawnDaemon() resolves tsx.cmd / npx.cmd on Windows, runs via shell with
  per-token quoting (paths with spaces) and windowsVerbatimArguments.
- isDaemonRunning() skips the fs.access pre-check on Windows and probes the
  pipe directly.
- stale-socket cleanup is a no-op on Windows (named pipes self-clean).
- setup.ts daemon-failure message uses the actual DAEMON_SOCKET_PATH.

Closes #7

1 files changed, 2 insertions, 1 deletions

diff --git a/src/setup.ts b/src/setup.ts
index 561a343..1ff7c36 100644
--- a/src/setup.ts
+++ b/src/setup.ts
@@ -8,6 +8,7 @@ import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
 import { execSync } from "node:child_process";
 import type { BrowserClient } from "./client";
 import { ensureDaemon } from "./daemon/spawn";
+import { DAEMON_SOCKET_PATH } from "./daemon/protocol";
 
 // ── Public: register the /browser-setup slash command ──────────────────────
 
@@ -41,7 +42,7 @@ export async function performSetup(client: BrowserClient): Promise<SetupResult>
   // Step 2: Start the browser daemon (spawns if not running, silently reuses if alive)
   const daemonReady = await ensureDaemon();
   if (!daemonReady) {
-    return { success: false, error: "Could not start the browser daemon. Check /tmp/pi-browser-daemon.sock." };
+    return { success: false, error: `Could not start the browser daemon. Check ${DAEMON_SOCKET_PATH}.` };
   }
 
   // Step 3: Connect to Chrome DevTools