refactor(load-graph): make hidden module dependencies explicit

Phase 2 of the load-graph project. I fixed the seven hidden dependencies the classification surfaced, so each module declares what it uses instead of relying on init order.

- system-defaults now requires host-environment and user-constants at runtime. They were eval-when-compile only, but env-bsd-p and user-home-dir are read at load, so the compiled module couldn't load standalone.
- custom-buffer-file, dev-fkeys, calendar-sync, and video-audio-recording require keybindings and drop their (when (boundp 'cj/custom-keymap) ...) shims. The shim silently dropped the C-; binding when the module loaded before keybindings. The explicit require makes the dependency real.
- flycheck-config and mail-config require keybindings for their cj/custom-keymap bindings (a use-package :map and a direct keymap-set).
- Removed a dead eval-when-compile (defvar cj/custom-keymap) in transcription-config; nothing there used the variable.

No init.el load-order change. keybindings and the foundation modules already load before these, so the requires are no-ops at startup and only fix standalone and test loading.

I verified each fix with a fresh emacs --batch (require 'X), then swept all modules standalone: every one loads or fails only with a clear missing-package message. Full make test, make validate-modules, and an init smoke all pass. Module headers and the inventory's hidden-dependency section are updated to mark the seven resolved.

1 files changed, 9 insertions, 12 deletions

diff --git a/modules/system-defaults.el b/modules/system-defaults.el
index 33d93bbc..8ef6181a 100644
--- a/modules/system-defaults.el
+++ b/modules/system-defaults.el
@@ -11,11 +11,9 @@
 ;; Top-level side effects: mutates global defaults (many `setq'), advises
 ;;   `display-warning', adds a `display-buffer-alist' entry, remaps one global
 ;;   key.
-;; Runtime requires: autorevert, server, bookmark; host-environment
-;;   (`env-bsd-p') and user-constants (`user-home-dir') are read at load but
-;;   currently only required via eval-when-compile — Phase 2 to make explicit.
-;; Direct test load: conditional (host-environment and user-constants must load
-;;   first; the compiled module cannot resolve them standalone yet).
+;; Runtime requires: autorevert, server, bookmark, host-environment
+;;   (`env-bsd-p'), user-constants (`user-home-dir').
+;; Direct test load: yes.
 ;;
 ;; Loads during init to set sane defaults: UTF-8 everywhere, quiet prompts, synced clipboards,
 ;; and hands-off async shell buffers. Nothing to call—just launch Emacs and the environment is ready.
@@ -31,13 +29,12 @@
 (require 'server)
 (require 'bookmark)
 
-;; `host-environment' and `user-constants' are loaded earlier in init.el,
-;; so they are available at runtime when this module loads.  The
-;; `eval-when-compile' forms here are byte-compile hints to silence
-;; free-variable / free-function warnings when this module is compiled
-;; in isolation; no runtime requires are needed.
-(eval-when-compile (require 'host-environment))
-(eval-when-compile (require 'user-constants))
+;; host-environment (`env-bsd-p') and user-constants (`user-home-dir') are read
+;; at load time below, so require them at runtime, not only at compile time.
+;; init.el already loads them earlier; the explicit requires let this module
+;; load standalone.
+(require 'host-environment)
+(require 'user-constants)
 
 ;; -------------------------- Native Comp Preferences --------------------------