Update summarization model to GPT-OSS with fallback chain (#41)

Changed default AI model for summarization:
- Primary: openai/gpt-oss-120b:presto
- Fallback 1: openai/gpt-oss-20b:presto
- Fallback 2: anthropic/claude-haiku-4.5

Added new models to the models object for better organization.

Co-authored-by: Claude <noreply@anthropic.com>

Author: carterworks

src/services/ai.ts

@@ -21,23 +21,32 @@ const models = Object.freeze({
 			nano: "openai/gpt-5-nano", // $0.05/1M input, $0.40/1M output,
 			mini: "openai/gpt-5-mini", // $0.25/1M input, $2.00/1M output,
 		},
+		gptOss: {
+			presto120b: "openai/gpt-oss-120b:presto",
+			presto20b: "openai/gpt-oss-20b:presto",
+		},
 	},
 	google: {
 		gemini2dot5: {
 			flash: "google/gemini-2.5-flash", // $0.30/1M input, $2.50/1M output
 			flashLite: "google/gemini-2.5-flash-lite", // $0.10/1M input, $0.40/1M output
 		},
 	},
+	anthropic: {
+		claude: {
+			haiku45: "anthropic/claude-haiku-4.5",
+		},
+	},
 });
 
 export async function fetchCompletion(
 	systemPrompt: string,
 	userPrompt: string,
 	reasoning: "minimal" | "low" | "medium" | "high" = "medium",
-	model = models.openai.gpt5.nano,
+	model = models.openai.gptOss.presto120b,
 	fallbackModels = [
-		models.google.gemini2dot5.flashLite,
-		models.openai.gpt5.mini,
+		models.openai.gptOss.presto20b,
+		models.anthropic.claude.haiku45,
 	],
 ) {
 	if (!AI_ENABLED) {