Anthropic Cache TTL is hard-coded

[ammario]

This should be user-defined as there's a cost trade-off we shouldn't centrally mandate:

cmux/src/utils/ai/cacheStrategy.ts

Lines 22 to 36 in c8589ed

	return messages.map((msg, index) => {
	if (index === cacheIndex) {
	return {
	...msg,
	providerOptions: {
	anthropic: {
	cacheControl: {
	type: "ephemeral" as const,
	ttl: "5m",
	},
	},
	},
	};
	}
	return msg;