Add native Windows support (#91)

- Native Windows daemon using TCP loopback endpoints
- Direct-mode fallback for CLI/daemon compatibility
- Comment operations over RPC
- PowerShell installer script
- Go 1.24 requirement
- Cross-OS testing documented

Co-authored-by: danshapiro <danshapiro@users.noreply.github.com>
Amp-Thread-ID: https://ampcode.com/threads/T-c6230265-055f-4af1-9712-4481061886db
Co-authored-by: Amp <amp@ampcode.com>

internal/rpc/transport_unix.go

@@ -0,0 +1,22 @@
+//go:build !windows
+
+package rpc
+
+import (
+	"net"
+	"os"
+	"time"
+)
+
+func listenRPC(socketPath string) (net.Listener, error) {
+	return net.Listen("unix", socketPath)
+}
+
+func dialRPC(socketPath string, timeout time.Duration) (net.Conn, error) {
+	return net.DialTimeout("unix", socketPath, timeout)
+}
+
+func endpointExists(socketPath string) bool {
+	_, err := os.Stat(socketPath)
+	return err == nil
+}