feat: Support specifying the compression model to use when compressing a session for greater cost controls

src/config/app_config.rs

@@ -66,6 +66,7 @@ pub struct AppConfig {
     pub save_session: Option<bool>,
     pub compression_threshold: usize,
     pub compression_keep_last: usize,
+    pub compression_model: Option<String>,
     pub summarization_prompt: Option<String>,
     pub summary_context_prompt: Option<String>,
     pub max_tool_result_chars: Option<usize>,
@@ -156,6 +157,7 @@ impl Default for AppConfig {
             save_session: None,
             compression_threshold: 4000,
             compression_keep_last: 0,
+            compression_model: None,
             summarization_prompt: None,
             summary_context_prompt: None,
             max_tool_result_chars: None,
@@ -247,6 +249,7 @@ impl AppConfig {
             save_session: config.save_session,
             compression_threshold: config.compression_threshold,
             compression_keep_last: config.compression_keep_last,
+            compression_model: config.compression_model,
             summarization_prompt: config.summarization_prompt,
             summary_context_prompt: config.summary_context_prompt,
             max_tool_result_chars: config.max_tool_result_chars,