fix: resolve mem-cli build errors

Fix u32 vs i32 type mismatch in agent_handler for PostgreSQL binding
Remove unused imports and variables

crates/mem-cli/src/handlers/agent_handler.rs

@@ -121,7 +121,7 @@ pub async fn register_agent_handler(
     .bind(&body.agent_id)
     .bind(&body.capabilities)
     .bind(&body.webhook_url)
-    .bind(body.rate_limit.unwrap_or(1000))
+    .bind(body.rate_limit.unwrap_or(1000) as i32)
     .execute(&state.pool)
     .await;
 

crates/mem-ingest/src/entity_extractor.rs

@@ -44,7 +44,7 @@ impl ExtractedEntity {
 #[async_trait]
 pub trait EntityExtractor: Send + Sync {
     async fn extract(&self, text: &str) -> Result<Vec<ExtractedEntity>>;
-    async fn extract_with_auth(&self, text: &str, x_forward_user: Option<&str>) -> Result<Vec<ExtractedEntity>> {
+    async fn extract_with_auth(&self, text: &str, _x_forward_user: Option<&str>) -> Result<Vec<ExtractedEntity>> {
         // Default: ignore auth header, use regular extract
         self.extract(text).await
     }