fix: 工具广场统一18000端口 + 去除电量限制 + bot头像更新

nginx反代(tools-nginx.conf)：
- 10个工具统一通过18000端口路径分发
- 解决/static/冲突（Lama精确匹配，其余给LibreTranslate）
- 解决/api/冲突（PDF用sub_filter改为/pdf-api/，/api/给imgcompress）
- Overleaf兜底处理所有未匹配的绝对路径
- 前端工具卡片统一走18000端口+路径

后端：
- 去除对话电量限制（validateUser中的num扣减逻辑）

前端：
- bot头像更新为战知logo（蓝底白字）
- LaTeX公式编辑器"复制为图片"改为"下载为图片"（解决跨域问题）

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/tools-nginx.conf

@@ -0,0 +1,133 @@
+server {
+    listen 18000;
+    client_max_body_size 500M;
+
+    # 1. Stirling PDF
+    location /pdf/ {
+        proxy_pass http://127.0.0.1:18080/;
+        proxy_set_header Host $host;
+        proxy_set_header Accept-Encoding "";
+        proxy_buffering off;
+        sub_filter_once off;
+        sub_filter '"/api/' '"/pdf-api/';
+    }
+    location /pdf-api/ {
+        proxy_pass http://127.0.0.1:18080/api/;
+        proxy_set_header Host $host;
+        proxy_buffering off;
+        client_max_body_size 500M;
+    }
+
+    # 2. Excalidraw
+    location /draw/ {
+        proxy_pass http://127.0.0.1:18081/;
+        proxy_set_header Host $host;
+    }
+    location /assets/ { proxy_pass http://127.0.0.1:18081/assets/; }
+    location /v1/ai/ {
+        proxy_pass http://127.0.0.1:18082/v1/ai/;
+        proxy_set_header Host $host;
+        proxy_read_timeout 60s;
+        proxy_buffering off;
+    }
+
+    # 3. TrWebOCR
+    location /ocr/ {
+        proxy_pass http://127.0.0.1:18083/;
+        proxy_set_header Host $host;
+        proxy_buffering off;
+    }
+
+    # 4. LibreTranslate
+    location /translate/ {
+        proxy_pass http://127.0.0.1:18084/;
+        proxy_set_header Host $host;
+    }
+
+    # 5. PPTist
+    location /ppt/ {
+        proxy_pass http://127.0.0.1:18085/;
+        proxy_set_header Host $host;
+        proxy_buffering off;
+    }
+    location /pptapi/ {
+        proxy_pass http://127.0.0.1:18086/;
+        proxy_http_version 1.1;
+        proxy_set_header Connection "";
+        proxy_buffering off;
+        proxy_cache off;
+    }
+
+    # 6. imgcompress
+    location /imgcompress/ {
+        proxy_pass http://127.0.0.1:18087/;
+        proxy_set_header Host $host;
+    }
+
+    # 7. Lama Cleaner
+    location /lama/ {
+        proxy_pass http://127.0.0.1:18088/;
+        proxy_set_header Host $host;
+        proxy_buffering off;
+    }
+    location /lama/inpaint {
+        proxy_pass http://127.0.0.1:18088/inpaint;
+        proxy_set_header Host $host;
+        proxy_buffering off;
+        proxy_read_timeout 300s;
+        client_max_body_size 500M;
+    }
+    # Lama Cleaner 的2个精确static文件
+    location /static/js/main.1bd455bc.js { proxy_pass http://127.0.0.1:18088/static/js/main.1bd455bc.js; }
+    location /static/css/main.c28d98ca.css { proxy_pass http://127.0.0.1:18088/static/css/main.c28d98ca.css; }
+
+    # /static/ 其余的给 LibreTranslate
+    location /static/ { proxy_pass http://127.0.0.1:18084/static/; }
+
+    # LibreTranslate 绝对路径 API
+    location /languages { proxy_pass http://127.0.0.1:18084/languages; }
+    location /frontend/settings { proxy_pass http://127.0.0.1:18084/frontend/settings; }
+    location /detect { proxy_pass http://127.0.0.1:18084/detect; }
+
+    # imgcompress 绝对路径
+    location /_next/ { proxy_pass http://127.0.0.1:18087/_next/; }
+    location /api/ {
+        proxy_pass http://127.0.0.1:18087/api/;
+        proxy_set_header Host $host;
+        proxy_buffering off;
+        client_max_body_size 500M;
+    }
+
+    # 8. webp2jpg
+    location /webp2jpg/ {
+        proxy_pass http://127.0.0.1:18089/;
+        proxy_set_header Host $host;
+    }
+    location /cdn/ { proxy_pass http://127.0.0.1:18089/cdn/; }
+
+    # 9. Overleaf
+    location /overleaf/ {
+        proxy_pass http://127.0.0.1:18090/;
+        proxy_set_header Host $host;
+        proxy_http_version 1.1;
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection "upgrade";
+        proxy_buffering off;
+    }
+
+    # 10. LaTeX 公式编辑器
+    location /latex/ {
+        proxy_pass http://127.0.0.1:18091/;
+        proxy_set_header Host $host;
+    }
+
+    # 默认回落到 Overleaf
+    location / {
+        proxy_pass http://127.0.0.1:18090;
+        proxy_set_header Host $host;
+        proxy_http_version 1.1;
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection "upgrade";
+        proxy_buffering off;
+    }
+}