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, 13 insertions, 17 deletions

diff --git a/modules/calendar-sync.el b/modules/calendar-sync.el
index 4d1ea219..21ef8727 100644
--- a/modules/calendar-sync.el
+++ b/modules/calendar-sync.el
@@ -13,11 +13,8 @@
 ;; Top-level side effects: defines a calendar keymap and conditionally registers
 ;;   it under cj/custom-keymap; timer and network fetches guarded by
 ;;   config/noninteractive checks.
-;; Runtime requires: cl-lib, subr-x, system-lib, cj-org-text-lib. keybindings is
-;;   needed for the C-; g binding but only reached through a boundp guard, so the
-;;   binding silently drops standalone. Phase 2 fix.
-;; Direct test load: conditional (C-; g registration skipped without keybindings;
-;;   private config optional).
+;; Runtime requires: cl-lib, subr-x, system-lib, cj-org-text-lib, keybindings.
+;; Direct test load: yes (private config optional; degrades cleanly when absent).
 ;;
 ;; Simple, reliable one-way sync from multiple calendars to Org mode.
 ;; Downloads .ics files from calendar URLs (Google, Proton, etc.) and
@@ -87,6 +84,7 @@
 (require 'subr-x)
 (require 'system-lib)  ;; provides cj/auth-source-secret-value (leaf; no ai-config dep)
 (require 'cj-org-text-lib)
+(require 'keybindings)  ;; provides cj/custom-keymap
 
 (defun calendar-sync--log-silently (format-string &rest args)
   "Log FORMAT-STRING with ARGS without requiring the full config."
@@ -1705,18 +1703,16 @@ Syncs all calendars immediately, then every `calendar-sync-interval-minutes'."
   "S" #'calendar-sync-start
   "x" #'calendar-sync-stop)
 
-;; Only set up keybindings if cj/custom-keymap exists (not in test environment)
-(when (boundp 'cj/custom-keymap)
-  (keymap-set cj/custom-keymap "g" cj/calendar-map)
-
-  (with-eval-after-load 'which-key
-    (which-key-add-key-based-replacements
-      "C-; g" "calendar sync menu"
-      "C-; g s" "sync now"
-      "C-; g i" "sync status"
-      "C-; g t" "toggle auto-sync"
-      "C-; g S" "start auto-sync"
-      "C-; g x" "stop auto-sync")))
+(keymap-set cj/custom-keymap "g" cj/calendar-map)
+
+(with-eval-after-load 'which-key
+  (which-key-add-key-based-replacements
+    "C-; g" "calendar sync menu"
+    "C-; g s" "sync now"
+    "C-; g i" "sync status"
+    "C-; g t" "toggle auto-sync"
+    "C-; g S" "start auto-sync"
+    "C-; g x" "stop auto-sync"))
 
 ;;; Initialization