feat: add cache toggle, unregister API and chunk training docs

- Add POST /api/v1/config/cache for cache toggle
- Add POST /api/v1/unregister for video deletion
- Add CHUNK_DATA_STRUCTURE.md for marcom training
- Fix processor_results query in delete_video

src/api/server.rs

@@ -148,6 +148,30 @@ struct SearchRequest {
     uuid: Option<String>,
 }
 
+#[derive(Debug, Deserialize)]
+struct CacheToggleRequest {
+    enabled: bool,
+}
+
+#[derive(Debug, Serialize)]
+struct CacheToggleResponse {
+    success: bool,
+    cache_enabled: bool,
+    message: String,
+}
+
+#[derive(Debug, Deserialize)]
+struct UnregisterRequest {
+    uuid: String,
+}
+
+#[derive(Debug, Serialize)]
+struct UnregisterResponse {
+    success: bool,
+    uuid: String,
+    message: String,
+}
+
 #[derive(Debug, Serialize, Deserialize)]
 struct SearchResult {
     uuid: String,
@@ -1300,6 +1324,56 @@ async fn get_job(
     Ok(Json(response))
 }
 
+async fn cache_toggle(
+    State(_state): State<AppState>,
+    Json(req): Json<CacheToggleRequest>,
+) -> Result<Json<CacheToggleResponse>, StatusCode> {
+    tracing::info!("[cache_toggle] Setting cache enabled to: {}", req.enabled);
+
+    crate::core::config::set_cache_enabled(req.enabled);
+
+    let response = CacheToggleResponse {
+        success: true,
+        cache_enabled: req.enabled,
+        message: if req.enabled {
+            "Cache enabled".to_string()
+        } else {
+            "Cache disabled".to_string()
+        },
+    };
+
+    tracing::info!("[cache_toggle] SUCCESS");
+    Ok(Json(response))
+}
+
+async fn unregister(
+    State(state): State<AppState>,
+    Json(req): Json<UnregisterRequest>,
+) -> Result<Json<UnregisterResponse>, StatusCode> {
+    tracing::info!("[unregister] Unregistering video: {}", req.uuid);
+
+    let db = &state.api_state.db;
+
+    match db.delete_video(&req.uuid).await {
+        Ok(_) => {
+            tracing::info!("[unregister] SUCCESS - deleted: {}", req.uuid);
+            Ok(Json(UnregisterResponse {
+                success: true,
+                uuid: req.uuid,
+                message: "Video unregistered successfully".to_string(),
+            }))
+        }
+        Err(e) => {
+            tracing::error!("[unregister] ERROR - {}", e);
+            Ok(Json(UnregisterResponse {
+                success: false,
+                uuid: req.uuid,
+                message: format!("Failed to unregister: {}", e),
+            }))
+        }
+    }
+}
+
 pub async fn start_server(host: &str, port: u16) -> anyhow::Result<()> {
     let _ = SERVER_START.set(Instant::now());
 
@@ -1319,6 +1393,7 @@ pub async fn start_server(host: &str, port: u16) -> anyhow::Result<()> {
 
     let protected_routes = Router::new()
         .route("/api/v1/register", post(register))
+        .route("/api/v1/unregister", post(unregister))
         .route("/api/v1/probe", post(probe))
         .route("/api/v1/search", post(search))
         .route("/api/v1/n8n/search", post(n8n_search))
@@ -1328,6 +1403,7 @@ pub async fn start_server(host: &str, port: u16) -> anyhow::Result<()> {
         .route("/api/v1/progress/:uuid", get(get_progress))
         .route("/api/v1/jobs", get(list_jobs))
         .route("/api/v1/jobs/:uuid", get(get_job))
+        .route("/api/v1/config/cache", post(cache_toggle))
         .layer(axum::middleware::from_fn_with_state(
             state.api_state.clone(),
             api_key_validation,