refactor: introduce doom-context

Introduces a system to announce what execution contexts are active, so I
can react appropriately, emit more helpful logs/warnings in the case of
issues, and throw more meaningful errors.

* bin/doom: load module CLIs in the 'modules' context.
* lisp/cli/doctor.el: load package files in 'packages' context.
* lisp/doom-cli.el:
  - (doom-before-init-hook, doom-after-init-hook): trigger hooks at the
    correct time. This may increase startup load time, as the benchmark
    now times more of the startup process.
  - (doom-cli-execute, doom-cli-context-execute,
    doom-cli-context-restore, doom-cli-context-parse,
    doom-cli--output-benchmark-h, doom-cli-call, doom-cli--restart,
    doom-cli-load, run!): remove redundant context prefix in debug logs,
    it's now redundant with doom-context, which doom-log now prefixes
    them with.
* lisp/doom-lib.el (doom-log): prefix doom-context to doom-log output,
  unless it starts with :.
* lisp/doom-packages.el (package!, doom-packages--read): throw error if
  not used in a packages.el file or in the context of our package
  manager.
* lisp/doom-profiles.el (doom-profile--generate-init-vars,
  doom-profile--generate-load-modules): use modules doom-context instead
  of doom-init-time to detect startup.
* lisp/doom-start.el (doom-load-packages-incrementally-h): move function
  closer to end of doom-after-init-hook.
* lisp/doom.el:
  - (doom-before-init-hook, doom--set-initial-values-h,
    doom--begin-init-h): rename doom--set-initial-values-h to
    doom--begin-init-h and ensure it runs as late in
    doom-before-init-hook as possible, as that is the point where Doom's
    "initialization" formally begins.
  - (doom-after-init-hook): don't trigger at the end of command-line-1
    in non-interactive sessions. This will be triggered manually in
    doom-cli.el's run!.
* lisp/lib/config.el (doom/reload, doom/reload-autoloads,
  doom/reload-env): use 'reload' context for reload commands.
* modules/lang/emacs-lisp/autoload.el (+emacs-lisp-eval): use 'eval'
  context.
* modules/lang/org/config.el: remove doom-reloading-p; check for
  'reload' doom context instead.

lisp/lib/config.el

@@ -11,10 +11,6 @@
 (defvar doom-before-reload-hook nil
   "A list of hooks to run before `doom/reload' has reloaded Doom.")
 
-;;;###autoload
-(defvar doom-reloading-p nil
-  "TODO")
-
 ;;;###autoload
 (defun doom/open-private-config ()
   "Browse your `doom-user-dir'."
@@ -85,7 +81,7 @@ Runs `doom-after-reload-hook' afterwards."
   (interactive)
   (mapc #'require (cdr doom-incremental-packages))
   (doom--if-compile (format "%S sync -e" doom-bin)
-      (let ((doom-reloading-p t))
+      (doom-with-context '(reload modules)
         (doom-run-hooks 'doom-before-reload-hook)
         (doom-load (file-name-concat doom-user-dir doom-module-init-file) t)
         (with-demoted-errors "PRIVATE CONFIG ERROR: %s"
@@ -110,10 +106,11 @@ line."
   (interactive)
   (require 'doom-profiles)
   ;; TODO: Make this more robust
-  (dolist (file (mapcar #'car doom-profile-generators))
-    (when (string-match-p "/[0-9]+-loaddefs[.-]" file)
-      (load (doom-path doom-profile-dir doom-profile-init-dir-name file)
-            'noerror))))
+  (doom-with-context 'reload
+    (dolist (file (mapcar #'car doom-profile-generators))
+      (when (string-match-p "/[0-9]+-loaddefs[.-]" file)
+        (load (doom-path doom-profile-dir doom-profile-init-dir-name file)
+              'noerror)))))
 
 ;;;###autoload
 (defun doom/reload-env ()
@@ -125,10 +122,11 @@ Doing so from within Emacs will taint your shell environment.
 An envvar file contains a snapshot of your shell environment, which can be
 imported into Emacs."
   (interactive)
-  (let ((default-directory doom-emacs-dir))
-    (with-temp-buffer
-      (doom-load-envvars-file doom-env-file)
-      (message "Reloaded %S" (abbreviate-file-name doom-env-file)))))
+  (doom-with-context 'reload
+    (let ((default-directory doom-emacs-dir))
+      (with-temp-buffer
+        (doom-load-envvars-file doom-env-file)
+        (message "Reloaded %S" (abbreviate-file-name doom-env-file))))))
 
 ;;;###autoload
 (defun doom/upgrade ()