Handle and show ratelimits based on the api http header

[d-oit]

If HTTP Header included the rate limit handle information, use these values instead of the static rateLimitSeconds:

https://docs.anthropic.com/en/api/rate-limits#response-headers
https://platform.openai.com/docs/guides/rate-limits

Output rate limits with a standard code (like 429 or API_RATE_LIMIT) for all Handler

Show details as vs code notification or vs code output channel.

Sample:

protected async handleRateLimit(response: Response): Promise {
const rateLimitRemaining = response.headers.get("x-rate-limit-remaining")
const rateLimitReset = response.headers.get("x-rate-limit-reset")

	if (rateLimitRemaining !== null && rateLimitReset !== null) {
		const remaining = parseInt(rateLimitRemaining, 10)
		const resetTime = new Date(parseInt(rateLimitReset, 10) * 1000)

		if (remaining <= 0) {
			const message = `Rate limit exceeded. Retry after ${resetTime.toLocaleString()}`
			vscode.window.showErrorMessage(message)
		} else {
			const message = `Rate limit almost reached. ${remaining} requests remaining.`
			vscode.window.showWarningMessage(message)
		}
	} else {
		const message = "Rate limit details not found in the response headers."
		vscode.window.showErrorMessage(message)
	}
}