feat(ssl): add inter-site jitter and clear rate-limit messaging to ssl-renew

[mrrobot47]

Problem

ssl-renew --all fires per-site ACME operations back-to-back with no spacing, and on a Let's Encrypt rate limit authorize() shows a misleading "you're in a local environment or using a non-public domain" message instead of saying it's a rate limit.

Fix

• Jitter between actual renewals: in renew_ssl_cert(), after the "is renewal due / --force" check, a sleep( random_int( 1, 5 ) ) before every real renewal except the first in the process, to avoid bursting against Let's Encrypt's new-order/burst limits. Sites that aren't due (almost all of them on a normal night) and single-site ee site ssl-renew <site> never sleep. The flag is a process-wide static because --all renews every site in one process.
• Clear rate-limit messaging: is_rate_limit_exception() detects rate limits via RateLimitedServerException (acmephp maps every rateLimited ACME problem to it), plus a rateLimited marker in the message. authorize() and both executeRenewal() catches then say "Let's Encrypt rate limit hit for: … Please wait before retrying." with the rate-limits docs link. A rate limit hit while revoking the previous authorizations (the first new-order of every renewal) is now caught there too, so the renewal reports the rate limit instead of crashing.

With this change a rate-limited site returns false and ssl-renew --all continues. Other uncaught exceptions or EE::error() in one site still abort the whole batch (pre-existing; out of scope).

Out of scope (follow-ups)

A fully failure-resilient --all with automatic backoff-and-retry, and removing the dead if ( $all ) branch in ssl_renew(), are larger changes left for later.

Note for merge

This edits executeRenewal()'s catch blocks, which #486 also edits — whichever merges second will need a small rebase to reconcile.

Testing

Manual: ssl-renew --all with several LE sites that aren't due runs without any sleep; with two or more due sites there is a 1–5s pause before each renewal after the first. The rate-limit path was verified against acmephp with a mocked 429 rateLimited response (both authorize() and the revoke-then-authorize renewal flow print the rate-limit message and return false); unrelated errors such as "Too many open files" or rejectedIdentifier keep their own messages.

Tested on Ubuntu 26.04 with EasyEngine 4.12.0 with five sites flagged as Let's Encrypt (three not due, two due), and on PHP 7.4 and 8.5 for the rate-limit handling.

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.