fix(ocr): 页面文件不足防护——双重预检+长期冷却

问题：EasyOCR worker启动报 WinError 1455（页面文件太小），
无法加载 cufft64_11.dll，物理内存充足但虚拟内存(已提交32.5/35.7GB)不足。

修复：
1. worker端：import前预检虚拟内存——剩余<2GB则直接exit(2)，不进入torch/easyocr加载
2. worker端：import捕获WinError 1455时写入虚拟内存诊断信息（物理/页面/提交率）
3. 父进程端：启动worker前预检虚拟内存——<2GB直接冷却1小时，不启动worker
4. 父进程端：识别exit(2)/页面文件错误——冷却1小时而非30秒（系统级问题不反复重试）

诊断增强：
- _get_virtual_memory_info()：通过Win32 API获取物理/虚拟内存/页面文件状态
- 崩溃日志包含完整虚拟内存快照，便于排查
- 日志明确提示'增大Windows页面文件'

easyocr_worker.py

@@ -19,6 +19,36 @@ import traceback
 from datetime import datetime
 
 # ── 崩溃日志文件：写入源码目录根（easyocr_crash.log），统一管理、便于父进程读取 ──
+def _get_virtual_memory_info() -> dict:
+    """获取虚拟内存（页面文件）状态，用于诊断 WinError 1455。"""
+    try:
+        import ctypes
+        class MEMORYSTATUSEX(ctypes.Structure):
+            _fields_ = [
+                ("dwLength", ctypes.c_ulong),
+                ("dwMemoryLoad", ctypes.c_ulong),
+                ("ullTotalPhys", ctypes.c_ulonglong),
+                ("ullAvailPhys", ctypes.c_ulonglong),
+                ("ullTotalPageFile", ctypes.c_ulonglong),
+                ("ullAvailPageFile", ctypes.c_ulonglong),
+                ("ullTotalVirtual", ctypes.c_ulonglong),
+                ("ullAvailVirtual", ctypes.c_ulonglong),
+                ("ullAvailExtendedVirtual", ctypes.c_ulonglong),
+            ]
+        mem = MEMORYSTATUSEX()
+        mem.dwLength = ctypes.sizeof(MEMORYSTATUSEX)
+        ctypes.windll.kernel32.GlobalMemoryStatusEx(ctypes.byref(mem))
+        return {
+            "total_phys_gb": round(mem.ullTotalPhys / (1024**3), 1),
+            "avail_phys_gb": round(mem.ullAvailPhys / (1024**3), 1),
+            "total_pagefile_gb": round(mem.ullTotalPageFile / (1024**3), 1),
+            "avail_pagefile_gb": round(mem.ullAvailPageFile / (1024**3), 1),
+            "commit_pct": round((1 - mem.ullAvailPageFile / max(mem.ullTotalPageFile, 1)) * 100, 1),
+        }
+    except Exception:
+        return {}
+
+
 def _get_crash_log_path() -> str:
     try:
         base = os.path.dirname(os.path.abspath(__file__))
@@ -67,11 +97,37 @@ try:
     os.environ.setdefault("OMP_NUM_THREADS", "1")
     os.environ.setdefault("MKL_NUM_THREADS", "1")
 
+    # ── 预检：虚拟内存是否足够加载 CUDA 库（cufft64_11.dll ~800MB） ──
+    _vm = _get_virtual_memory_info()
+    if _vm and _vm.get("avail_pagefile_gb", 99) < 2.0:
+        _msg = (
+            f"页面文件不足: 剩余{_vm.get('avail_pagefile_gb', '?')}GB"
+            f"(提交{_vm.get('commit_pct', '?')}%)"
+            f"，CUDA库需要≥2GB连续虚拟地址空间"
+        )
+        _write_crash_log(f"{datetime.now()} [easyocr_worker] 页面文件预检失败: {_msg}")
+        _flush_exit(f"页面文件不足: {_msg}", code=2)
+
     from PIL import Image
     import numpy as np
     import easyocr
 except Exception as e:
-    _flush_exit(f"import 失败: {e}\n{traceback.format_exc()}")
+    _vm = _get_virtual_memory_info()
+    _vm_hint = ""
+    if _vm:
+        _vm_hint = (
+            f"\n[virtual memory] 物理内存: {_vm.get('avail_phys_gb',0)}/{_vm.get('total_phys_gb',0)} GB"
+            f" | 页面文件: {_vm.get('avail_pagefile_gb',0)}/{_vm.get('total_pagefile_gb',0)} GB"
+            f" | 提交使用率: {_vm.get('commit_pct',0)}%"
+        )
+    # WinError 1455 = 页面文件太小 → 标记为永久失败，不重试
+    _is_pagefile_error = "1455" in str(e) or "页面文件" in str(e)
+    _exit_code = 2 if _is_pagefile_error else 1  # exit(2) = 虚拟内存不足
+    _write_crash_log(
+        f"{datetime.now()} [easyocr_worker] import {_exit_code}: "
+        f"{'页面文件不足' if _is_pagefile_error else 'import失败'}: {e}{_vm_hint}"
+    )
+    _flush_exit(f"import 失败{'(页面文件不足)' if _is_pagefile_error else ''}: {e}{_vm_hint}", code=_exit_code)
 
 
 def _init_reader():