fix(ai-chat): drop redundant "(free)" from LFM2.5-2.6B display name

Scope the change to just the Liquid AI LFM2.5-2.6B model via the
per-model override list instead of stripping "(free)" from every
OpenRouter free-tier model.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018q5AWeB6pvt3LPHYxknis6

src/backend/drivers/ai-chat/providers/openrouter/OpenRouterProvider.ts

@@ -268,17 +268,12 @@ export class OpenRouterProvider implements IChatProvider {
             if (!microcentCosts.request) {
                 microcentCosts.request = 0;
             }
-            // OpenRouter appends "(free)" to the display name of its free-tier
-            // model variants. The ":free" model id already conveys that, so
-            // drop the redundant suffix from the human-facing name.
-            const displayName = model.name.replace(/\s*\(free\)\s*$/i, '');
             coerced_models.push({
                 id: `openrouter:${model.id}`,
-                name: `${displayName} (OpenRouter)`,
+                name: `${model.name} (OpenRouter)`,
                 aliases: [
                     model.id,
                     model.name,
-                    displayName,
                     `openrouter/${model.id}`,
                     model.id.split('/').slice(1).join('/'),
                 ],

src/backend/drivers/ai-chat/providers/openrouter/modelOverrides.ts

@@ -26,4 +26,10 @@ export const OPEN_ROUTER_MODEL_OVERRIDES: IChatModel[] = [
         subscriberOnly: true,
         minimumCredits: toMicroCents(2),
     } as IChatModel,
+    {
+        // OpenRouter names this model "Liquid AI: LFM2.5-2.6B (free)"; drop
+        // the redundant "(free)" suffix (the ":free" id already conveys it).
+        id: 'openrouter:liquid/lfm-2.5-2.6b:free',
+        name: 'Liquid AI: LFM2.5-2.6B (OpenRouter)',
+    } as IChatModel,
 ];