feat(02-03): client socket, autostart daemon, switch handler, workspace wiring

- Client struct sends JSON requests to daemon over Unix socket
- EnsureDaemon auto-starts the daemon if not running (retry 50ms x 20)
- Switch handler uses FuzzyMatch + SwitchToWorkspace via i3 IPC
- InitWorkspaceResolver wires BuildTerminalWorkspaceMap + ResolveWorkspace
- sysattr_linux.go for Setsid detach on daemon spawn

sysattr_linux.go

@@ -0,0 +1,7 @@
+package main
+
+import "syscall"
+
+func newSysProcAttr() *syscall.SysProcAttr {
+	return &syscall.SysProcAttr{Setsid: true}
+}