fix: add tokenizer fallback for claude-haiku-4-5

Map claude-haiku-4-5 to claude-3.5-haiku tokenizer as temporary
workaround until ai-tokenizer adds native support for the newer
model.

Author: ThomasK33

src/utils/main/tokenizer.ts

@@ -17,6 +17,9 @@ export interface Tokenizer {
 
 const MODEL_KEY_OVERRIDES: Record<string, string> = {
   "anthropic:claude-sonnet-4-5": "anthropic/claude-sonnet-4.5",
+  // FIXME(ThomasK33): Temporary workaround since ai-tokenizer does not yet
+  // claude-haiku-4.5
+  "anthropic:claude-haiku-4-5": "anthropic/claude-3.5-haiku",
 };
 
 const DEFAULT_WARM_MODELS = [