fix(ai): correct thinking budget for 2.5-flash-lite models (#2861)

The 2.5-flash-lite model was incorrectly matching the 2.5-flash
case, setting minimal budget to 128. Per Google's docs, flash-lite's
minimum thinking budget is 512, not 128. This caused the error:

  The thinking budget 128 is invalid. Please choose a value between
  512 and 24576.

Add a dedicated 2.5-flash-lite case before the 2.5-flash case so
the more specific match takes priority.

Fixes #2838

Co-authored-by: JasonOA888 <JasonOA888@users.noreply.github.com>

packages/ai/src/providers/google.ts

@@ -462,6 +462,16 @@ function getGoogleBudget(
 		return budgets[effort];
 	}
 
+	if (model.id.includes("2.5-flash-lite")) {
+		const budgets: Record<ClampedThinkingLevel, number> = {
+			minimal: 512,
+			low: 2048,
+			medium: 8192,
+			high: 24576,
+		};
+		return budgets[effort];
+	}
+
 	if (model.id.includes("2.5-flash")) {
 		const budgets: Record<ClampedThinkingLevel, number> = {
 			minimal: 128,