fix: neutral hint form for remaining client-facing tool mentions, Limits bounds accessor

Fix round 1 (task 10 review):
- FieldValidator's "unknown field" validation error (reaches the
  client via validation_failed's fields) and PostPresenter's
  DIVI_HINT (surfaced in the result's hints array) still named
  lit-content-types/lit-content-update as plain lit-<name>; converted
  both to the neutral "lit/<name> (direkt: lit-<name>)" form like the
  other hints from task 10. Re-grepped src/ for any other client-facing
  error/field/hints text naming a direct-by-default tool as lit-<name>
  (descriptions/schemas excluded per Q11c) - none left.
- Added Limits::bounds() (field => [min, max]) and made LimitsTab use
  it for the number inputs' min/max instead of a second, hardcoded
  copy of the same bounds.
- LimitsTab now shows a description note when the configured upload_mb
  exceeds wp_max_upload_size() (PHP's upload_max_filesize/post_max_size),
  since WordPress would refuse a larger upload before this limit ever
  applies.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

src/Limits.php

@@ -39,6 +39,17 @@ final class Limits
         return self::sanitize(get_option(self::OPTION, []));
     }
 
+    /**
+     * The [min, max] each field is clamped to by sanitize() – for admin UI form attributes,
+     * so they can't drift from the actual bounds.
+     *
+     * @return array<string, array{int, int}>
+     */
+    public static function bounds(): array
+    {
+        return self::BOUNDS;
+    }
+
     /**
      * Settings API sanitize callback: always returns all keys, clamped to their bounds.
      *