feat: 识图提速（模型常驻/精简模板/磁盘缓存）+ WebUI 上传压缩 + 缓存清理脚本

- vision.ts: keep_alive:-1 常驻显存（治冷加载 7.7GB）；转录缓存持久化
  data/agent/vision-cache.json（重启后历史图秒回）；hook 转录用精简模板
- ChatInput/image-attachments: 上传 JPEG 长边>1600px 自动压缩 q0.85
- scripts/cleanup-cache.mjs: npm/opengrep 缓存、过期会话、旧图瘦身清理
- README 双语同步

pi-web/components/ChatInput.tsx

@@ -6,6 +6,7 @@ import { clearDraft, getDraft, setDraft, type ChatDraftImage } from "@/lib/draft
 import {
   MAX_ATTACHED_IMAGE_BYTES,
   MAX_ATTACHED_IMAGES,
+  compressImageFile,
   isBase64ImageWithinLimits,
 } from "@/lib/image-attachments";
 import {
@@ -390,20 +391,21 @@ export const ChatInput = forwardRef<ChatInputHandle, Props>(function ChatInput({
     pendingImageCountRef.current += imageFiles.length;
     try {
       const newImages = await Promise.all(
-        imageFiles.map(
-          (file) =>
-            new Promise<AttachedImage>((resolve, reject) => {
-              const reader = new FileReader();
-              reader.onload = () => {
-                const result = reader.result as string;
-                // result is "data:<mime>;base64,<data>"
-                const base64 = result.split(",")[1];
-                resolve({ data: base64, mimeType: file.type, previewUrl: URL.createObjectURL(file) });
-              };
-              reader.onerror = reject;
-              reader.readAsDataURL(file);
-            })
-        )
+        imageFiles.map(async (file) => {
+          // 大 JPEG 先压缩（长边 1600/q0.85），会话不再内嵌数 MB base64，加载/传输/转录都更快
+          const compressed = await compressImageFile(file);
+          const base64 = await new Promise<string>((resolve, reject) => {
+            const reader = new FileReader();
+            reader.onload = () => resolve((reader.result as string).split(",")[1]);
+            reader.onerror = reject;
+            reader.readAsDataURL(compressed);
+          });
+          return {
+            data: base64,
+            mimeType: compressed.type,
+            previewUrl: URL.createObjectURL(compressed),
+          };
+        })
       );
       setAttachedImages((prev) => {
         const accepted = newImages.slice(0, Math.max(0, MAX_ATTACHED_IMAGES - prev.length));

pi-web/lib/image-attachments.ts

@@ -1,6 +1,11 @@
 export const MAX_ATTACHED_IMAGE_BYTES = 10 * 1024 * 1024;
 export const MAX_ATTACHED_IMAGES = 10;
 
+/** 上传时自动压缩：长边超过此像素的 JPEG 缩到此边长（相机照片主场景，视觉模型输入上限 ~1344px，1600 无损）。 */
+export const MAX_IMAGE_EDGE_PX = 1600;
+/** JPEG 重编码质量：避免伪影糊掉边缘/小字。 */
+export const IMAGE_JPEG_QUALITY = 0.85;
+
 export interface Base64ImageAttachment {
   data: string;
   mimeType: string;
@@ -37,6 +42,41 @@ export function isBase64ImageWithinLimits(value: unknown): value is Base64ImageA
   return bytes !== null && bytes <= MAX_ATTACHED_IMAGE_BYTES;
 }
 
+/**
+ * 上传前压缩：仅 JPEG 且长边超过 MAX_IMAGE_EDGE_PX 时缩放重编码（EXIF 方向由
+ * createImageBitmap 默认 from-image 纠正）。PNG/WebP/GIF 原样返回（无损/动画场景）。
+ * 重编码无收益（更小或失败）时退回原文件。
+ */
+export async function compressImageFile(file: File): Promise<File> {
+  if (file.type !== "image/jpeg") return file;
+  let bitmap: ImageBitmap;
+  try {
+    bitmap = await createImageBitmap(file);
+  } catch {
+    return file; // 解码失败退化为原文件
+  }
+  try {
+    const edge = Math.max(bitmap.width, bitmap.height);
+    if (edge <= MAX_IMAGE_EDGE_PX) return file; // 本就不大，避免无谓重编码
+    const scale = MAX_IMAGE_EDGE_PX / edge;
+    const width = Math.max(1, Math.round(bitmap.width * scale));
+    const height = Math.max(1, Math.round(bitmap.height * scale));
+    const canvas = document.createElement("canvas");
+    canvas.width = width;
+    canvas.height = height;
+    const ctx = canvas.getContext("2d");
+    if (!ctx) return file;
+    ctx.drawImage(bitmap, 0, 0, width, height);
+    const blob = await new Promise<Blob | null>((resolve) =>
+      canvas.toBlob(resolve, "image/jpeg", IMAGE_JPEG_QUALITY)
+    );
+    if (!blob || blob.size >= file.size) return file; // 重编码无收益则用原文件
+    return new File([blob], file.name.replace(/\.\w+$/, ".jpg"), { type: "image/jpeg" });
+  } finally {
+    bitmap.close();
+  }
+}
+
 /** Return an API-safe error for prompt, steering, and follow-up image arrays. */
 export function validateAgentImages(value: unknown): string | null {
   if (value === undefined) return null;