video2slides: 新 app — 长视频抽帧 + 逐帧差异 + 拖阈值挑幻灯片

Rust + axum + cube-core，前端纯静态单页。ffmpeg 每 N 秒抽一帧（限宽
1280），image crate 逐帧灰度 MAE 算差异；前端拖阈值实时把相近帧变灰、
关键变化高亮，悬停出彩色大图，分页 + toolbar 常驻。按 X-Client-Id 分目录
隔离，存储走 hostPath。镜像非 scratch：debian-slim + ffmpeg + musl binary。

Cargo.toml

@@ -12,6 +12,7 @@ members = [
     "apps/llm-proxy",
     "apps/write",
     "apps/webgl",
+    "apps/video2slides",
 ]
 
 [workspace.package]
@@ -32,6 +33,8 @@ rusqlite = { version = "0.32", features = ["bundled"] }
 reqwest = { version = "0.12", default-features = false, features = ["json", "rustls-tls", "stream", "multipart"] }
 futures = "0.3"
 tokio-stream = "0.1"
+image = { version = "0.25", default-features = false, features = ["jpeg"] }
+uuid = { version = "1", features = ["v4"] }
 
 [profile.release]
 opt-level = "z"