Telegram: fix model button review issues

- Add currentModel to callback handler for checkmark display
- Add 64-byte callback_data limit protection (skip long model IDs)
- Add tests for large model lists and callback_data limits

src/telegram/model-buttons.ts

@@ -31,6 +31,7 @@ export type ModelsKeyboardParams = {
 };
 
 const MODELS_PAGE_SIZE = 8;
+const MAX_CALLBACK_DATA_BYTES = 64;
 
 /**
  * Parse a model callback_data string into a structured object.
@@ -132,6 +133,12 @@ export function buildModelsKeyboard(params: ModelsKeyboardParams): ButtonRow[] {
     : currentModel;
 
   for (const model of pageModels) {
+    const callbackData = `mdl_sel_${provider}/${model}`;
+    // Skip models that would exceed Telegram's callback_data limit
+    if (Buffer.byteLength(callbackData, "utf8") > MAX_CALLBACK_DATA_BYTES) {
+      continue;
+    }
+
     const isCurrentModel = model === currentModelId;
     const displayText = truncateModelId(model, 38);
     const text = isCurrentModel ? `${displayText} ✓` : displayText;
@@ -139,7 +146,7 @@ export function buildModelsKeyboard(params: ModelsKeyboardParams): ButtonRow[] {
     rows.push([
       {
         text,
-        callback_data: `mdl_sel_${provider}/${model}`,
+        callback_data: callbackData,
       },
     ]);
   }