refactor: replace Box<dyn Error> with anyhow::Result

- ingestion_pipeline::run_worker_loop returns anyhow::Result<()>
- api_router::ApiState::new returns anyhow::Result<Self>
- html_router::HtmlState::new_with_resources is infallible, returns Self
- main/server/worker binary entry points return anyhow::Result<()>

api-router/src/api_state.rs

@@ -16,7 +16,7 @@ impl ApiState {
     pub async fn new(
         config: &AppConfig,
         storage: StorageManager,
-    ) -> Result<Self, Box<dyn std::error::Error>> {
+    ) -> anyhow::Result<Self> {
         let surreal_db_client = Arc::new(
             SurrealDbClient::new(
                 &config.surrealdb_address,