fix(desktop): dedupe mesh models across @main/plain id forms

desktop/src-tauri/src/mesh_llm/mod.rs

@@ -636,11 +636,24 @@ fn push_model(out: &mut Vec<MeshModelOption>, id: &str, name: Option<String>) {
     });
 }
 
+/// Canonical model id for equality/dedup. A serving node advertises the same
+/// model under two strings — `org/model@main:Q4` (serveTargets[].modelId) and
+/// `org/model:Q4` (available_models) — so keying on the raw string leaves BOTH
+/// in the picker. Strip the `@main` ref-qualifier (matching the selection-time
+/// rule in `pick_serve_target_for_model`) so the two collapse to one entry.
+pub(super) fn canonical_model_id(value: &str) -> String {
+    value.trim().replace("@main", "")
+}
+
 pub(super) fn dedupe_models(models: Vec<MeshModelOption>) -> Vec<MeshModelOption> {
+    // Key by canonical id so `@main` / non-`@main` forms of the same model
+    // dedup together. Display the canonical (stripped) id so the UI shows one
+    // stable label; selection still matches because the picker canonicalizes
+    // both sides too.
     let mut by_id = BTreeMap::<String, Option<String>>::new();
     for model in models {
         by_id
-            .entry(model.id)
+            .entry(canonical_model_id(&model.id))
             .and_modify(|name| {
                 if name.is_none() {
                     *name = model.name.clone();

desktop/src-tauri/src/mesh_llm/mod_tests.rs

@@ -53,6 +53,34 @@ fn sdk_ready_models_are_parsed_from_real_status_shape() {
     );
 }
 
+#[test]
+fn dedupe_models_collapses_at_main_and_plain_forms() {
+    // Regression: a serving node advertises the SAME model under two strings —
+    // `org/model@main:Q4` (serveTargets[].modelId) and `org/model:Q4`
+    // (available_models). Keying on the raw id left BOTH in the picker (the
+    // "two model listing" bug). They must dedup to a single canonical entry.
+    let models = vec![
+        super::MeshModelOption {
+            id: "unsloth/gemma-4-E4B-it-GGUF@main:Q4_K_M".to_string(),
+            name: None,
+        },
+        super::MeshModelOption {
+            id: "unsloth/gemma-4-E4B-it-GGUF:Q4_K_M".to_string(),
+            name: Some("Gemma 4".to_string()),
+        },
+    ];
+
+    let deduped = super::dedupe_models(models);
+    assert_eq!(
+        deduped,
+        vec![super::MeshModelOption {
+            id: "unsloth/gemma-4-E4B-it-GGUF:Q4_K_M".to_string(),
+            name: Some("Gemma 4".to_string()),
+        }],
+        "@main and plain forms of the same model must collapse to one entry"
+    );
+}
+
 #[test]
 fn requested_model_is_not_ready_while_sdk_is_in_standby() {
     let payload = json!({