merge: maestro/tsk_FUQws_DMIcXa [tsk_FUQws_DMIcXa] mTLS/CA + 引导 token 框架

解决与 Go 骨架(1A)的 add/add 冲突：go.mod 统一 module 路径为
github.com/wangjia/pangolin/server，require 取并集；setup.sh 合并两边意图。
go build ./... 与 go test ./internal/mtls/... 通过。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/setup.sh

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
-# Run once after cloning to download dependencies and generate go.sum.
+# Run once after cloning: download dependencies, generate go.sum, run unit tests.
 set -euo pipefail
 cd "$(dirname "$0")"
 go mod tidy
+go test ./internal/mtls/...
 echo "setup complete — run 'make build' to verify"