feat: add Google code retrieval across desktop CLI and MCP

apps/desktop/src-tauri/src/main.rs

@@ -119,6 +119,8 @@ fn set_cpu_threads(threads: usize, state: State<'_, AppState>) -> Result<Setting
 
 #[derive(Default, Deserialize)]
 struct Filters {
+    #[serde(default)]
+    code_only: bool,
     folder: Option<PathBuf>,
     extension: Option<String>,
     min_size: Option<u64>,
@@ -132,6 +134,7 @@ struct Filters {
 impl From<Filters> for SearchOptions {
     fn from(value: Filters) -> Self {
         Self {
+            code_only: value.code_only,
             folder: value.folder,
             extension: value.extension,
             min_size: value.min_size,
@@ -500,6 +503,53 @@ fn main() {
 mod tests {
     use super::*;
 
+    #[test]
+    fn code_scope_defaults_off_and_combines_with_other_filters() {
+        let legacy: Filters = serde_json::from_str(r#"{"extension":"rs"}"#).unwrap();
+        let legacy: SearchOptions = legacy.into();
+        assert!(!legacy.code_only);
+        let scoped: Filters =
+            serde_json::from_str(r#"{"code_only":true,"extension":"rs","min_size":10}"#).unwrap();
+        let scoped: SearchOptions = scoped.into();
+        assert!(scoped.code_only);
+        assert_eq!(scoped.extension.as_deref(), Some("rs"));
+        assert_eq!(scoped.min_size, Some(10));
+        assert!(serde_json::from_str::<Filters>(r#"{"code_only":"true"}"#).is_err());
+    }
+
+    #[test]
+    fn code_scope_reaches_real_keyword_search_without_model_readiness() {
+        let root = tempfile::tempdir().unwrap();
+        std::fs::write(
+            root.path().join("parse.rs"),
+            "fn parse_configuration() { /* validate config */ }",
+        )
+        .unwrap();
+        std::fs::write(
+            root.path().join("notes.md"),
+            "parse_configuration validate config",
+        )
+        .unwrap();
+        let mut index = SearchIndex::open(":memory:").unwrap();
+        index.index_folder(root.path()).unwrap();
+        let all: SearchOptions = Filters::default().into();
+        assert_eq!(
+            index
+                .search_with_options("parse_configuration", 10, &all)
+                .unwrap()
+                .len(),
+            2
+        );
+        let scoped: SearchOptions = serde_json::from_str::<Filters>(r#"{"code_only":true}"#)
+            .unwrap()
+            .into();
+        let hits = index
+            .search_with_options("parse_configuration", 10, &scoped)
+            .unwrap();
+        assert_eq!(hits.len(), 1);
+        assert_eq!(hits[0].filename, "parse.rs");
+    }
+
     #[test]
     fn measured_failure_retains_closed_trace_without_inventing_results() {
         let mut trace = TraceCollector::new(MetricsMode::Debug);