fix(dev): repair hunk jump, F4 hook leak, async clone, and nil guards

- vc-config: C-; v d matched literal +/- source text via consult-line, not gutter hunks. It now completes over git-gutter's hunk list and jumps to the chosen line.
- vc-config: clipboard clone ran git synchronously, freezing every frame for the whole clone. It now runs async with a sentinel that opens the clone on success and surfaces the process buffer on failure.
- vc-config: magit-blame bound D and S to the same command. D is now difftastic-magit-diff, matching the transient.
- vc-config: dropped the :commands autoload for git-timemachine-show-selected-revision, a function the package never defined. The phantom appeared in M-x and errored.
- dev-fkeys: both F4 chained-compile handlers armed a hook on the global compilation-finish-functions before their compile ran, so a quit left it live and the next unrelated compile fired the chain. The one-shot hook now installs buffer-locally in the compilation buffer, same shape as the projectile cache-revert hooks.
- test-runner: outside a project with no global test directory, three commands crashed with wrong-type-argument on a nil path. Discovery now returns nil and the commands signal user-error.
- diff-config: removed the global "-w" ediff default, which made every session ignore whitespace (indentation-only changes compared as identical). Whitespace-ignore stays available as ediff's per-session toggle.
- restclient-config: the C-; R bindings went through raw global-set-key, silently depending on keybindings.el loading first. They now use a prefix keymap registered like the other C-; prefixes.
- httpd-config: simple-httpd loaded on a 1s timer and created www/ on every startup. It now defers until impatient-mode needs it, and the doc root is created at package load.

6 files changed, 123 insertions, 53 deletions

diff --git a/modules/dev-fkeys.el b/modules/dev-fkeys.el
index 80b43600..0f120a8d 100644
--- a/modules/dev-fkeys.el
+++ b/modules/dev-fkeys.el
@@ -82,13 +82,25 @@ recognized markers both return nil."
 
 ;; ---------- Action handlers ----------
 
+(defun cj/--f4-install-once-hook (buffer then-fn)
+  "Install a one-shot buffer-local compilation finish hook in BUFFER.
+Installing in the compilation buffer itself (rather than globally)
+means a quit before the compile starts, or an unrelated concurrent
+compile, can never fire the chained THEN-FN.  No-op when BUFFER is not
+a live buffer."
+  (when (buffer-live-p buffer)
+    (with-current-buffer buffer
+      (add-hook 'compilation-finish-functions
+                (cj/--f4-make-once-hook then-fn) nil t))))
+
 (defun cj/--f4-compile-and-run-impl ()
   "Run `projectile-compile-project', then `projectile-run-project' on success.
-Installs a one-shot `compilation-finish-functions' hook to chain the run."
-  (add-hook 'compilation-finish-functions
-            (cj/--f4-make-once-hook
-             (lambda () (projectile-run-project nil))))
-  (projectile-compile-project nil))
+Chains the run via a one-shot finish hook installed buffer-locally in
+the compilation buffer projectile returns."
+  (let ((result (projectile-compile-project nil)))
+    (cj/--f4-install-once-hook
+     (cj/--projectile-compilation-buffer result)
+     (lambda () (projectile-run-project nil)))))
 
 (defun cj/--f4-dispatch (action)
   "Route ACTION (a symbol from `cj/--f4-candidates') to its handler.
@@ -109,24 +121,26 @@ command (prompted-and-cached by projectile) drives the build."
   (let ((clean-cmd (cj/--f4-derive-clean-cmd root)))
     (unless clean-cmd
       (user-error "Clean + Rebuild: no clean command for this project type"))
-    (add-hook 'compilation-finish-functions
-              (cj/--f4-make-once-hook
-               (lambda () (projectile-compile-project nil))))
-    (let ((default-directory root))
-      (compile clean-cmd))))
+    (let* ((default-directory root)
+           (buffer (compile clean-cmd)))
+      (cj/--f4-install-once-hook
+       buffer (lambda () (projectile-compile-project nil))))))
 
 ;; ---------- One-shot compilation-finish hook ----------
 
 (defun cj/--f4-make-once-hook (then-fn)
   "Build a one-shot `compilation-finish-functions' hook that chains THEN-FN.
 The returned lambda removes itself from `compilation-finish-functions' on
-first invocation regardless of status, then calls THEN-FN only if the
-status string starts with \"finished\" (the convention used by compile.el
-for a successful compile)."
+first invocation regardless of status — from both the global value and
+the running buffer's local value, so it is one-shot wherever it was
+installed — then calls THEN-FN only if the status string starts with
+\"finished\" (the convention used by compile.el for a successful
+compile)."
   (let (hook)
     (setq hook
           (lambda (_buf status)
             (remove-hook 'compilation-finish-functions hook)
+            (remove-hook 'compilation-finish-functions hook t)
             (when (and (stringp status)
                        (string-prefix-p "finished" status))
               (funcall then-fn))))
diff --git a/modules/diff-config.el b/modules/diff-config.el
index 0c09b951..75911587 100644
--- a/modules/diff-config.el
+++ b/modules/diff-config.el
@@ -40,7 +40,6 @@
   :custom
   (ediff-window-setup-function  'ediff-setup-windows-plain)
   (ediff-split-window-function  'split-window-horizontally)
-  (ediff-diff-options            "-w")
   (ediff-highlight-all-diffs    nil)
   :bind-keymap ("C-c D" . cj/ediff-map)
   :init
diff --git a/modules/httpd-config.el b/modules/httpd-config.el
index 1a2a5c61..a3ae0fac 100644
--- a/modules/httpd-config.el
+++ b/modules/httpd-config.el
@@ -5,8 +5,9 @@
 ;;
 ;; Layer: 4 (Optional).
 ;; Category: O/D/P.
-;; Load shape: eager.
-;; Eager reason: none; local web server, a command-loaded deferral candidate.
+;; Load shape: deferred.
+;; Defer reason: impatient-mode requires simple-httpd on demand; nothing
+;; needs the server (or its www/ root) at startup.
 ;; Top-level side effects: package configuration via use-package.
 ;; Runtime requires: none.
 ;; Direct test load: yes.
@@ -17,14 +18,15 @@
 ;;;; -------------------------- Simple-Httpd -------------------------
 
 (use-package simple-httpd
-  :defer 1
+  :defer t
   :preface
   (defconst cj/httpd-wwwdir (concat user-emacs-directory "www"))
   (defun cj/httpd-check-or-create-wwwdir ()
     (unless (file-exists-p cj/httpd-wwwdir)
       (make-directory cj/httpd-wwwdir)))
-  :init (cj/httpd-check-or-create-wwwdir)
   :config
+  ;; Create the doc root only when the server package actually loads.
+  (cj/httpd-check-or-create-wwwdir)
   (setq httpd-root cj/httpd-wwwdir)
   (setq httpd-show-backtrace-when-error t)
   (setq httpd-serve-files t))
diff --git a/modules/restclient-config.el b/modules/restclient-config.el
index 0511eddb..497f54d0 100644
--- a/modules/restclient-config.el
+++ b/modules/restclient-config.el
@@ -8,7 +8,7 @@
 ;; Load shape: eager.
 ;; Eager reason: none; API exploration, a command-loaded deferral candidate.
 ;; Top-level side effects: package configuration via use-package.
-;; Runtime requires: none (configures packages via use-package).
+;; Runtime requires: keybindings (C-; R prefix registration).
 ;; Direct test load: yes.
 ;;
 ;; Integrates restclient.el for interactive API exploration from within Emacs.
@@ -23,6 +23,8 @@
 
 ;;; Code:
 
+(require 'keybindings)  ;; cj/register-prefix-map
+
 ;; --------------------------------- Constants ---------------------------------
 
 (defvar cj/restclient-data-dir (expand-file-name "data/" user-emacs-directory)
@@ -61,12 +63,15 @@
 
 ;; -------------------------------- Keybindings --------------------------------
 
-(global-set-key (kbd "C-; R n") #'cj/restclient-new-buffer)
-(global-set-key (kbd "C-; R o") #'cj/restclient-open-file)
+(defvar-keymap cj/restclient-map
+  :doc "Keymap for restclient operations"
+  "n" #'cj/restclient-new-buffer
+  "o" #'cj/restclient-open-file)
+
+(cj/register-prefix-map "R" cj/restclient-map "REST client")
 
 (with-eval-after-load 'which-key
   (which-key-add-key-based-replacements
-    "C-; R" "REST client"
     "C-; R n" "new scratch buffer"
     "C-; R o" "open .rest file"))
 
diff --git a/modules/test-runner.el b/modules/test-runner.el
index 7f157f1c..6cb35275 100644
--- a/modules/test-runner.el
+++ b/modules/test-runner.el
@@ -139,9 +139,11 @@ if not found or not in a project."
 		 (t cj/test-global-directory))))))
 
 (defun cj/test--get-test-files ()
-  "Return list of test file names (without path) in test directory."
+  "Return list of test file names (without path) in test directory.
+Returns nil when no test directory is available (outside a project
+with `cj/test-global-directory' unset)."
   (let ((dir (cj/test--get-test-directory)))
-	(when (file-directory-p dir)
+	(when (and dir (file-directory-p dir))
 	  (mapcar #'file-name-nondirectory
 			  (directory-files dir t "^test-.*\\.el$")))))
 
@@ -169,6 +171,8 @@ Returns: (cons \\='success loaded-count) on success,
   (interactive)
   (cj/test--ensure-test-dir-in-load-path)
   (let ((dir (cj/test--get-test-directory)))
+	(unless dir
+	  (user-error "No test directory: not in a project and cj/test-global-directory is unset"))
 	(unless (file-directory-p dir)
 	  (user-error "Test directory %s does not exist" dir))
 	(let ((test-files (directory-files dir t "^test-.*\\.el$")))
@@ -200,11 +204,12 @@ Returns: \\='success if added successfully,
   (cj/test--ensure-test-dir-in-load-path)
   (let* ((focused-files (cj/test--current-focused-files))
          (dir (cj/test--get-test-directory))
-		 (available-files (when (file-directory-p dir)
+		 (available-files (when (and dir (file-directory-p dir))
 							(mapcar #'file-name-nondirectory
 									(directory-files dir t "^test-.*\\.el$")))))
 	(if (null available-files)
-		(user-error "No test files found in %s" dir)
+		(user-error "No test files found in %s"
+					(or dir "any test directory (not in a project)"))
 	  (let* ((unfocused-files (cl-set-difference available-files
 												 focused-files
 												 :test #'string=))
diff --git a/modules/vc-config.el b/modules/vc-config.el
index 60fcaeb8..3da9266f 100644
--- a/modules/vc-config.el
+++ b/modules/vc-config.el
@@ -37,9 +37,13 @@
 (defvar forge-pull-notifications)
 (defvar forge-topic-list-limit)
 
+;; External package variables (buffer-local hunk list from git-gutter).
+(defvar git-gutter:diffinfos)
+
 ;; External package functions (from lazily-loaded packages).
 (declare-function git-gutter:next-hunk "git-gutter")
 (declare-function git-gutter:previous-hunk "git-gutter")
+(declare-function git-gutter-hunk-start-line "git-gutter")
 (declare-function git-timemachine--start "git-timemachine")
 (declare-function git-timemachine--revisions "git-timemachine")
 (declare-function git-timemachine-show-revision "git-timemachine")
@@ -100,8 +104,7 @@
 
 (use-package git-timemachine
   :commands (git-timemachine
-			 git-timemachine-show-revision
-			 git-timemachine-show-selected-revision)
+			 git-timemachine-show-revision)
   :init
   (defun cj/git-timemachine-show-selected-revision ()
   "Displays git revisions of file in chronological order adding metadata."
@@ -157,13 +160,33 @@
 	  (forge-create-issue)
 	(user-error "Not in a forge repository")))
 
+(defun cj/--git-gutter-hunk-candidates (start-lines)
+  "Build completion candidates for hunk START-LINES in the current buffer.
+Each candidate is a cons of a \"LINE: text\" label and the line number."
+  (mapcar (lambda (line)
+            (cons (format "%4d: %s" line
+                          (save-excursion
+                            (goto-char (point-min))
+                            (forward-line (1- line))
+                            (buffer-substring-no-properties
+                             (line-beginning-position) (line-end-position))))
+                  line))
+          start-lines))
+
 (defun cj/goto-git-gutter-diff-hunks ()
-  "Jump to git-gutter diff hunks using consult.
-Searches for lines starting with + or - (diff markers) and allows
-interactive selection to jump to any changed line in the buffer."
+  "Jump to a git-gutter hunk in the current buffer chosen with completion."
   (interactive)
   (require 'git-gutter)
-  (consult-line "^[+\\-]"))
+  (let ((candidates (cj/--git-gutter-hunk-candidates
+                     (mapcar #'git-gutter-hunk-start-line
+                             (and (boundp 'git-gutter:diffinfos)
+                                  git-gutter:diffinfos)))))
+    (unless candidates
+      (user-error "No git-gutter hunks in this buffer"))
+    (let ((line (cdr (assoc (completing-read "Hunk: " candidates nil t)
+                            candidates))))
+      (goto-char (point-min))
+      (forward-line (1- line)))))
 
 ;; ------------------------------ Git Clone Clipboard -----------------------------
 ;; Quick git clone from clipboard URL
@@ -180,6 +203,33 @@ scp form."
          (last (car (last (split-string trimmed "[/:]" t)))))
     (and last (file-name-sans-extension last))))
 
+(defun cj/--git-clone-open (clone-dir)
+  "Open CLONE-DIR's README when one exists, else `dired' the directory."
+  (let ((readme (seq-find
+                 (lambda (file)
+                   (string-match-p "\\`README" (upcase file)))
+                 (directory-files clone-dir))))
+    (if readme
+        (find-file (expand-file-name readme clone-dir))
+      (dired clone-dir))))
+
+(defun cj/--git-clone-make-sentinel (url clone-dir)
+  "Return a sentinel reporting the git clone of URL into CLONE-DIR.
+On a zero exit the sentinel announces success and opens the clone; on
+any other exit or a signal it surfaces the process buffer."
+  (lambda (process _event)
+    (when (memq (process-status process) '(exit signal))
+      (if (and (eq (process-status process) 'exit)
+               (zerop (process-exit-status process)))
+          (progn
+            (message "Cloned %s into %s" url clone-dir)
+            (cj/--git-clone-open clone-dir))
+        (let ((buf (process-buffer process)))
+          (when (buffer-live-p buf)
+            (pop-to-buffer buf))
+          (message "git clone of %s failed (status %s)"
+                   url (process-exit-status process)))))))
+
 (defun cj/git-clone-clipboard-url (url target-dir)
   "Clone git repository from clipboard URL to TARGET-DIR.
 
@@ -187,11 +237,13 @@ With no prefix argument: uses first directory in `cj/git-clone-dirs'.
 With \\[universal-argument]: choose from `cj/git-clone-dirs'.
 With \\[universal-argument] \\[universal-argument]: choose any directory.
 
-Clones with a direct `git' process (no shell), into a path derived
-robustly from URL.  Aborts with a clear message when the clipboard is
-empty, the target is not a writable directory, the destination already
-exists, or `git' exits non-zero.  After a successful clone, opens the
-repository's README if found, else `dired's the clone."
+Clones with a direct asynchronous `git' process (no shell, no frozen
+frames), into a path derived robustly from URL.  Aborts with a clear
+message when the clipboard is empty, the target is not a writable
+directory, or the destination already exists.  The process sentinel
+reports the result: on success it opens the repository's README if
+found (else `dired's the clone); on failure it surfaces the process
+buffer."
   (interactive
    (list (current-kill 0)  ;; Get URL from clipboard
          (cond
@@ -219,21 +271,14 @@ repository's README if found, else `dired's the clone."
       (when (file-exists-p clone-dir)
         (user-error "Clone destination already exists: %s" clone-dir))
       (message "Cloning %s into %s..." url clone-dir)
-      ;; Direct process, no shell.  `--' stops option parsing so a URL
-      ;; beginning with `-' can't be read as a git flag.
-      (let ((status (call-process "git" nil "*git-clone*" nil
-                                  "clone" "--" url clone-dir)))
-        (unless (zerop status)
-          (pop-to-buffer "*git-clone*")
-          (user-error "git clone failed (exit %d); see *git-clone*" status)))
-      ;; Find and open README
-      (let ((readme (seq-find
-                     (lambda (file)
-                       (string-match-p "\\`README" (upcase file)))
-                     (directory-files clone-dir))))
-        (if readme
-            (find-file (expand-file-name readme clone-dir))
-          (dired clone-dir))))))
+      ;; Direct async process, no shell, so no emacsclient frame blocks
+      ;; for the duration of the clone.  `--' stops option parsing so a
+      ;; URL beginning with `-' can't be read as a git flag.
+      (make-process
+       :name "git-clone"
+       :buffer "*git-clone*"
+       :command (list "git" "clone" "--" url clone-dir)
+       :sentinel (cj/--git-clone-make-sentinel url clone-dir)))))
 
 ;; -------------------------------- Difftastic ---------------------------------
 ;; Structural diffs for better git change visualization
@@ -243,7 +288,7 @@ repository's README if found, else `dired's the clone."
   :defer t
   :commands (difftastic-magit-diff difftastic-magit-show)
   :bind (:map magit-blame-read-only-mode-map
-              ("D" . difftastic-magit-show)
+              ("D" . difftastic-magit-diff)
               ("S" . difftastic-magit-show))
   :config
   (eval-after-load 'magit-diff