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, 9 insertions, 0 deletions

diff --git a/modules/external-open.el b/modules/external-open.el
index 57cffadc8..22e56a290 100644
--- a/modules/external-open.el
+++ b/modules/external-open.el
@@ -3,6 +3,15 @@
 ;;
 ;;; Commentary:
 ;;
+;; Layer: 2 (Core UX).
+;; Category: L/D.
+;; Load shape: eager.
+;; Eager reason: command library with no side effects; eager only by init order.
+;;   A deferral candidate (autoload commands) for Phase 4.
+;; Top-level side effects: none.
+;; Runtime requires: host-environment, system-lib, external-open-lib, cl-lib.
+;; Direct test load: yes (pure command helpers).
+;;
 ;; This library provides a simple mechanism for opening files with specific
 ;; extensions using your operating system’s default application rather than
 ;; visiting them in an Emacs buffer.  It offers: