Implement Upload Hook for momentry integration (Phase 1)

- Add upload_hook.rs module: trigger video_probe + video_register on upload
- Add UploadHookSection to config: video extensions, binary paths
- Integrate with SFTP: handle_close triggers hook on write files
- Integrate with SCP/rsync: child process exit triggers hook
- All 155 tests pass

markbase-core/src/config/mod.rs

@@ -18,6 +18,8 @@ pub struct AppConfig {
     pub sftp: SftpSection,
     #[serde(default)]
     pub ssh: SshSection,
+    #[serde(default)]
+    pub upload_hook: UploadHookSection,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -116,6 +118,36 @@ impl Default for SshSection {
     }
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct UploadHookSection {
+    pub enabled: bool,
+    pub video_probe_path: String,
+    pub video_register_cli: String,
+    pub video_register_dir: String,
+    pub video_extensions: Vec<String>,
+}
+
+impl Default for UploadHookSection {
+    fn default() -> Self {
+        Self {
+            enabled: false,
+            video_probe_path: "/Users/accusys/momentry_core_project/video_probe/target/release/video_probe".to_string(),
+            video_register_cli: "cli.py".to_string(),
+            video_register_dir: "/Users/accusys/momentry_core_project/video_register".to_string(),
+            video_extensions: vec![
+                "mp4".to_string(),
+                "mov".to_string(),
+                "avi".to_string(),
+                "mkv".to_string(),
+                "webm".to_string(),
+                "flv".to_string(),
+                "wmv".to_string(),
+                "m4v".to_string(),
+            ],
+        }
+    }
+}
+
 impl AppConfig {
     pub fn load(path: &str) -> Result<Self> {
         let config_path = std::path::PathBuf::from(path);
@@ -176,6 +208,9 @@ impl AppConfig {
             self.web.auth_db_path = v.clone();
             self.sftp.auth_db_path = v;
         }
+        if let Ok(v) = std::env::var("MB_UPLOAD_HOOK_ENABLED") {
+            self.upload_hook.enabled = v == "true" || v == "1";
+        }
     }
 }
 
@@ -192,6 +227,8 @@ mod tests {
         assert_eq!(config.ssh.port, 2024);
         assert_eq!(config.sftp.port, 2023);
         assert_eq!(config.s3.region, "us-east-1");
+        assert!(!config.upload_hook.enabled);
+        assert!(config.upload_hook.video_extensions.contains(&"mp4".to_string()));
     }
 
     #[test]