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/Integrations/WordPress/Content/PostPresenter.php

@@ -19,7 +19,7 @@ class PostPresenter
     public const DIVI_HINT = 'Dieser Inhalt ist mit Divi gebaut. Die Divi-Struktur wird über lit-divi-outline '
         . 'gelesen und mit den lit-divi-*-Tools bearbeitet; fehlen diese Tools, kann der Divi-Inhalt hier nicht '
         . 'bearbeitet werden. content wird deshalb nicht ausgegeben; Titel, Auszug, Felder und Begriffe sind '
-        . 'über lit-content-update änderbar.';
+        . 'über lit/content-update (direkt: lit-content-update) änderbar.';
 
     public function __construct(private ContentSchema $schema)
     {