feat(ai): add model caching, settings, and commands

- Introduce model caching with persistence to preferences
- Add provider default model and custom settings management
- Implement `/ai switch`, `/ai models`, and improve `/ai start`
- Add model name autocomplete for chat commands
- Update command definitions and help text
- Add unit tests for new functionality

src/config/preferences.c

@@ -1786,6 +1786,83 @@ prefs_free_ai_tokens(GList* tokens)
     }
 }
 
+gboolean
+prefs_ai_set_models(const char* const provider, const gchar* const* models, gint count)
+{
+    if (!provider || count <= 0)
+        return FALSE;
+
+    if (!prefs)
+        return FALSE;
+
+    /* Build semicolon-separated model list */
+    GString* model_str = g_string_new("");
+    for (int i = 0; i < count; i++) {
+        if (i > 0) {
+            g_string_append_c(model_str, ';');
+        }
+        g_string_append(model_str, models[i]);
+    }
+
+    g_key_file_set_string(prefs, PREF_GROUP_AI, g_strconcat(provider, "_models", NULL), model_str->str);
+    g_string_free(model_str, TRUE);
+    _save_prefs();
+    return TRUE;
+}
+
+gboolean
+prefs_ai_remove_models(const char* const provider)
+{
+    if (!provider)
+        return FALSE;
+
+    if (!prefs)
+        return FALSE;
+
+    auto_gchar gchar* key = g_strconcat(provider, "_models", NULL);
+    if (!g_key_file_has_key(prefs, PREF_GROUP_AI, key, NULL)) {
+        return FALSE;
+    }
+
+    g_key_file_remove_key(prefs, PREF_GROUP_AI, key, NULL);
+    _save_prefs();
+    return TRUE;
+}
+
+GList*
+prefs_ai_get_models(const char* const provider)
+{
+    if (!provider || !prefs)
+        return NULL;
+
+    auto_gchar gchar* key = g_strconcat(provider, "_models", NULL);
+    if (!g_key_file_has_key(prefs, PREF_GROUP_AI, key, NULL)) {
+        return NULL;
+    }
+
+    auto_gchar gchar* model_str = g_key_file_get_string(prefs, PREF_GROUP_AI, key, NULL);
+    if (!model_str || strlen(model_str) == 0) {
+        return NULL;
+    }
+
+    GList* result = NULL;
+    gchar** models = g_strsplit(model_str, ";", -1);
+    for (int i = 0; models[i] != NULL; i++) {
+        result = g_list_append(result, g_strdup(models[i]));
+    }
+    g_strfreev(models);
+
+    return result;
+}
+
+void
+prefs_free_ai_models(GList* models)
+{
+    if (models) {
+        g_list_free_full(models, g_free);
+    }
+}
+
 // get the preference group for a specific preference
 // for example the PREF_BEEP setting ("beep" in .profrc, see _get_key) belongs
 // to the [ui] section.

src/config/preferences.h

@@ -366,4 +366,10 @@ char* prefs_ai_get_token(const char* const provider);
 GList* prefs_ai_list_tokens(void);
 void prefs_free_ai_tokens(GList* tokens);
 
+/* AI model cache management */
+gboolean prefs_ai_set_models(const char* const provider, const gchar* const* models, gint count);
+gboolean prefs_ai_remove_models(const char* const provider);
+GList* prefs_ai_get_models(const char* const provider);
+void prefs_free_ai_models(GList* models);
+
 #endif