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/04-cgo-uninterruptible/exp14b/main.go

@@ -0,0 +1,43 @@
+//go:build ignore
+
+package main
+
+/*
+#cgo LDFLAGS: -ldl
+#include <dlfcn.h>
+#include <stdlib.h>
+typedef void (*fn)(void);
+static void call(void* f){ ((fn)f)(); }
+*/
+import "C"
+import (
+	"fmt"
+	"os"
+	"runtime"
+	"time"
+	"unsafe"
+)
+
+func threads() int { e,_ := os.ReadDir("/proc/self/task"); return len(e) }
+
+func main() {
+	p := C.CString("./hang.so"); h := C.dlopen(p, C.RTLD_NOW); C.free(unsafe.Pointer(p))
+	n := C.CString("hang_forever"); f := C.dlsym(h, n); C.free(unsafe.Pointer(n))
+	base := threads()
+	fmt.Printf("基线 threads=%d goroutines=%d\n\n", base, runtime.NumGoroutine())
+	for i := 1; i <= 20; i++ {
+		done := make(chan string, 1)
+		go func() { C.call(f); done <- "ok" }()
+		select {
+		case <-done:
+		case <-time.After(120 * time.Millisecond):
+		}
+		if i%5 == 0 {
+			fmt.Printf("  %2d 次卡死调用后: goroutines=%2d threads=%2d (+%d)\n",
+				i, runtime.NumGoroutine(), threads(), threads()-base)
+		}
+	}
+	fmt.Printf("\n结论: 20 次超时 → 泄漏 %d goroutine, %d OS 线程\n",
+		runtime.NumGoroutine()-1, threads()-base)
+	fmt.Println("每个卡在 cgo 里的 goroutine 独占一个 M（OS 线程），无法被抢占或回收")
+}