优化日志输出：斜杠命令执行时打印，过滤冗余的压缩日志

- 添加斜杠命令执行的 info 日志
- Context compression 日志只在实际触发压缩时输出 (debug级别)

src/agent/context_compressor.rs

@@ -110,17 +110,11 @@ impl ContextCompressor {
         // Check if compression is needed
         let tokens = estimate_tokens(&history);
         if tokens <= self.threshold() {
-            #[cfg(debug_assertions)]
-            tracing::info!(
-                tokens = tokens,
-                threshold = self.threshold(),
-                msg_count = history.len(),
-                "Context compression not needed"
-            );
             return Ok(history);
         }
 
-        tracing::info!(
+        #[cfg(debug_assertions)]
+        tracing::debug!(
             tokens = tokens,
             threshold = self.threshold(),
             msg_count = history.len(),
@@ -172,7 +166,8 @@ impl ContextCompressor {
             }
         }
 
-        tracing::info!(
+        #[cfg(debug_assertions)]
+        tracing::debug!(
             final_tokens = estimate_tokens(&current_history),
             final_msg_count = current_history.len(),
             "Context compression completed"

src/session/session.rs

@@ -265,6 +265,8 @@ impl SessionManager {
             .find(|c| c.name == command)
             .ok_or_else(|| AgentError::Other(format!("Unknown command: {}", command)))?;
 
+        tracing::info!(cmd = %cmd.name, args = ?args, "Executing slash command");
+
         match cmd.name {
             "new" => {
                 let title = args.map(|s| s.to_string());