docs(load-graph): classify core libraries and command modules

Third classification batch: the remaining core and library command modules from init.el's early block — external-open, media-utils, auth-config, keyboard-macros, system-utils, text-config, undead-buffers. I annotated each with the load-graph header contract, added a Batch 3 table to the inventory, and extended the validation allowlist. 23 of 102 modules are now classified.

No new hidden dependencies in this batch. auth-config stays eager because other modules need credentials early; the command libraries (external-open, media-utils, keyboard-macros) are eager only by init order and flagged as Phase 4 deferral candidates.

1 files changed, 10 insertions, 0 deletions

diff --git a/modules/system-utils.el b/modules/system-utils.el
index 432004038..7cf958674 100644
--- a/modules/system-utils.el
+++ b/modules/system-utils.el
@@ -3,6 +3,16 @@
 ;;
 ;;; Commentary:
 ;;
+;; Layer: 2 (Core UX).
+;; Category: L/C/S.
+;; Load shape: eager.
+;; Eager reason: registers global keys (C-c b, C-<f10>, list-buffers remap) and
+;;   a startup hook for its enhanced commands.
+;; Top-level side effects: three keymap-global-set, one emacs-startup-hook, plus
+;;   use-package configuration.
+;; Runtime requires: system-lib, external-open-lib.
+;; Direct test load: yes.
+;;
 ;; A "system-util" is an enhancement to common a Emacs command, or the extension
 ;; of an existing command. Perhaps this group can be better named.
 ;;