docs(plugin-arch): 归档插件架构迁移评估 + plan 第11节整改计划

- docs/zh/架构迁移评估.md: C ABI→子进程+共享内存完整迁移论证(1621行)
- docs/zh/experiments/: 18项可复跑可行性实验(架构评估的所有数字来源)
- plan.md §11: 11.1~11.9 插件架构缺陷修复清单(唯一权威编号)
- main 保持干净,本批次为 update 特性分支的整改起点

docs/zh/experiments/plugin-arch/02-feasibility/exp1_eventfd.go

@@ -0,0 +1,58 @@
+//go:build ignore
+package main
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func threads() int { e, _ := os.ReadDir("/proc/self/task"); return len(e) }
+
+func main() {
+	fmt.Println("=== 实验 1：eventfd 是否走 Go netpoller（只 park goroutine 不占 OS 线程）===")
+	base := threads()
+	fmt.Printf("基线线程数: %d (GOMAXPROCS=%d)\n\n", base, runtime.GOMAXPROCS(0))
+
+	const N = 200 // 模拟 200 个订阅者等待
+	var wg sync.WaitGroup
+	var woke int64
+	files := make([]*os.File, N)
+
+	for i := 0; i < N; i++ {
+		efd, err := unix.Eventfd(0, unix.EFD_NONBLOCK|unix.EFD_CLOEXEC)
+		if err != nil { fmt.Println("eventfd 失败:", err); return }
+		f := os.NewFile(uintptr(efd), fmt.Sprintf("evt%d", i))
+		files[i] = f
+		wg.Add(1)
+		go func(f *os.File) {
+			defer wg.Done()
+			buf := make([]byte, 8)
+			// 阻塞读：若走 netpoller 只 park goroutine
+			if _, err := f.Read(buf); err == nil {
+				atomic.AddInt64(&woke, 1)
+			}
+		}(f)
+	}
+
+	time.Sleep(500 * time.Millisecond) // 让所有 goroutine 进入等待
+	waiting := threads()
+	fmt.Printf("%d 个 goroutine 阻塞在 eventfd.Read 后:\n", N)
+	fmt.Printf("  线程数 = %d (增长 %d)\n", waiting, waiting-base)
+	if waiting-base < 20 {
+		fmt.Println("  ✅ 走 netpoller：线程未随等待者数量增长")
+	} else {
+		fmt.Printf("  ❌ 退化为阻塞 syscall：每个等待者占一个 OS 线程\n")
+	}
+
+	// 全部唤醒
+	one := []byte{1,0,0,0,0,0,0,0}
+	for _, f := range files { f.Write(one) }
+	wg.Wait()
+	fmt.Printf("\n唤醒数 = %d/%d  唤醒后线程数 = %d\n", woke, N, threads())
+}