feat(transcription): multilingual model catalog entries (T8.7, M4.2)

src-tauri/src/transcription/models.rs

@@ -12,6 +12,12 @@ struct Catalog {
     id: &'static str,
     label: &'static str,
     size_mb: u32,
+    /// `false` for the `.en` (English-only) ggml variants; `true` for the
+    /// multilingual variants, which whisper.cpp ships as the same filename
+    /// minus the `.en` infix (e.g. `ggml-base.bin` vs `ggml-base.en.bin`) —
+    /// same download/install machinery, just a different id/URL (T8.7,
+    /// FR-TRX-4, M4.2).
+    multilingual: bool,
 }
 
 const CATALOG: &[Catalog] = &[
@@ -19,21 +25,49 @@ const CATALOG: &[Catalog] = &[
         id: "tiny.en-q5_1",
         label: "Tiny (English, quantized) — fastest, least accurate",
         size_mb: 32,
+        multilingual: false,
     },
     Catalog {
         id: "base.en-q5_1",
         label: "Base (English, quantized) — balanced default",
         size_mb: 60,
+        multilingual: false,
     },
     Catalog {
         id: "small.en-q5_1",
         label: "Small (English, quantized) — more accurate, slower",
         size_mb: 190,
+        multilingual: false,
     },
     Catalog {
         id: "medium.en-q5_1",
         label: "Medium (English, quantized) — best accuracy, slowest",
         size_mb: 540,
+        multilingual: false,
+    },
+    Catalog {
+        id: "tiny-q5_1",
+        label: "Tiny (multilingual, quantized) — fastest, least accurate",
+        size_mb: 32,
+        multilingual: true,
+    },
+    Catalog {
+        id: "base-q5_1",
+        label: "Base (multilingual, quantized) — balanced default",
+        size_mb: 60,
+        multilingual: true,
+    },
+    Catalog {
+        id: "small-q5_1",
+        label: "Small (multilingual, quantized) — more accurate, slower",
+        size_mb: 190,
+        multilingual: true,
+    },
+    Catalog {
+        id: "medium-q5_1",
+        label: "Medium (multilingual, quantized) — best accuracy, slowest",
+        size_mb: 540,
+        multilingual: true,
     },
 ];
 
@@ -50,10 +84,19 @@ pub fn list(active_id: &str) -> Vec<ModelInfo> {
             size_mb: m.size_mb,
             installed: whisper_model_file(m.id).exists(),
             active: m.id == active_id,
+            multilingual: m.multilingual,
         })
         .collect()
 }
 
+/// Whether `id` names a multilingual (non-`.en`) catalog model — an unknown
+/// id (shouldn't happen; callers validate against the catalog first) is
+/// conservatively treated as English-only rather than granting language
+/// selection it can't honor.
+pub fn is_multilingual(id: &str) -> bool {
+    CATALOG.iter().any(|m| m.id == id && m.multilingual)
+}
+
 #[derive(Debug, thiserror::Error)]
 pub enum ModelError {
     #[error("unknown model id: {0}")]
@@ -147,4 +190,38 @@ mod tests {
         let err = remove(active, active).unwrap_err();
         assert!(matches!(err, ModelError::Invalid(_)));
     }
+
+    #[test]
+    fn catalog_has_a_multilingual_counterpart_for_every_english_only_size() {
+        // T8.7/M4.2: every `.en` model must have a same-size multilingual
+        // sibling so the Settings picker always has a language-capable
+        // option at whatever accuracy/speed tier the user already chose.
+        let en_only: Vec<_> = CATALOG.iter().filter(|m| !m.multilingual).collect();
+        let multilingual: Vec<_> = CATALOG.iter().filter(|m| m.multilingual).collect();
+        assert_eq!(en_only.len(), multilingual.len());
+        for en in &en_only {
+            assert!(
+                multilingual.iter().any(|m| m.size_mb == en.size_mb),
+                "no multilingual sibling for {}",
+                en.id
+            );
+        }
+    }
+
+    #[test]
+    fn is_multilingual_matches_the_catalog_flag() {
+        assert!(!is_multilingual("base.en-q5_1"));
+        assert!(is_multilingual("base-q5_1"));
+        // Unknown ids are conservatively English-only (no model to check).
+        assert!(!is_multilingual("nonexistent-id"));
+    }
+
+    #[test]
+    fn list_reports_multilingual_flag_per_model() {
+        let models = list("base.en-q5_1");
+        let base_en = models.iter().find(|m| m.id == "base.en-q5_1").unwrap();
+        let base_multi = models.iter().find(|m| m.id == "base-q5_1").unwrap();
+        assert!(!base_en.multilingual);
+        assert!(base_multi.multilingual);
+    }
 }