fix(formatter+telegram): drop tel: inline button, mark all 4xx as permanent

Pilot on washanyanya.ru exposed that Telegram Bot API rejects tel:
URLs in inline_keyboard with HTTP 400 "Wrong port number specified
in the URL". Queue was stuck on 5 items retrying the same failure
4 times each.

- MessageFormatter: always returns reply_markup = null. The phone
  number is already rendered in the '📱 ...' line, and mobile
  Telegram clients linkify it automatically.
- TelegramClient::is_permanent: treat all 4xx except 429 as permanent
  client-side errors, so future payload-shape bugs surface in the
  dashboard widget immediately instead of burning five retry cycles.
- MessageFormatterTest updated: the old test asserting tel: in
  reply_markup is replaced with one asserting reply_markup is null
  and the phone still appears in the text body.
- Spec §9 + §19 updated, §19's open question closed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

includes/class-telegram-client.php

@@ -64,13 +64,11 @@ final class TelegramClient
 
     private static function is_permanent(int $code, string $desc): bool
     {
-        if ($code === 401 || $code === 403) return true;
-        if ($code === 400) {
-            $d = strtolower($desc);
-            if (strpos($d, 'chat not found') !== false) return true;
-            if (strpos($d, 'bot was blocked') !== false) return true;
-            if (strpos($d, 'user is deactivated') !== false) return true;
-        }
+        // 4xx (except 429 rate-limit) are client-side errors: bad request,
+        // invalid chat, revoked token, malformed payload — retrying will not
+        // help. Mark as permanent so the queue gives up immediately and the
+        // admin is notified via the dashboard widget.
+        if ($code >= 400 && $code < 500 && $code !== 429) return true;
         return false;
     }
 }