feat(dev-fkeys): add project-aware F4 compile/run dispatcher

I added a new module `modules/dev-fkeys.el` that owns the dev F-key block. F4 prompts via `completing-read` with a candidate set filtered by project type (compiled / interpreted / unknown). C-F4 is the compile-only fast path. M-F4 is clean + rebuild. It runs a heuristic clean command derived from the project markers (go.mod, Cargo.toml, Eask, Makefile, CMakeLists.txt) and chains `projectile-compile-project` on success. S-F4 stays on `recompile` and now lives globally instead of duplicated across prog-general.el and prog-c.el. F6 is bound globally to `projectile-test-project` as a Phase 1 stopgap. Phase 2 replaces it with the polyglot test runner spec'd in todo.org.

Project-type detection runs against the projectile root and falls back to `unknown` when no marker matches. Interpreted markers are checked first so a Python or Node project with a Makefile for tasks classifies as interpreted instead of compiled. Compile + Run sequencing uses a one-shot `compilation-finish-functions` hook that self-removes on first invocation and only fires the follow-up when the status string starts with `finished`.

Cleanup in the same commit:
- Dropped F4/F5/F6 from `prog-general.el`'s prog-mode-hook. They are now global.
- Dropped F6→format bindings from prog-c.el / prog-python.el / prog-shell.el. C-; f was already bound in each, so this is pure removal.
- Dropped the duplicate S-F4 from prog-c.el. The global binding covers it.
- Updated the keybinding header in prog-general.el and the workflow comments in prog-c.el / prog-shell.el.
- Wired `(require 'dev-fkeys)` in init.el alongside coverage-core.

TDD: 73 tests across 11 files, one per helper. Production code is split into small testable internals (`cj/--detect-project-type`, `cj/--f4-candidates`, `cj/--f4-derive-clean-cmd`, `cj/--f4-make-once-hook`, `cj/--f4-dispatch`, `cj/--f4-compile-and-run-impl`, `cj/--f4-clean-rebuild-impl`, `cj/--f4-project-root`) plus three thin interactive wrappers. Smoke tests confirm bindings register on load.

Known limitation: if another `compilation-finish-functions` hook fires between my add-hook and the compile finishing, the chain can fire on the wrong compile. The hook self-removes on first invocation regardless of which compile it sees. Documented in the impl docstring. Acceptable for v1.

Phase 2 will replace F6 with the polyglot test runner (tree-sitter queries for Python/Go/TS, sexp scan for Elisp, buffer-local last-test memory).

1 files changed, 115 insertions, 0 deletions

diff --git a/tests/test-dev-fkeys--f4-make-once-hook.el b/tests/test-dev-fkeys--f4-make-once-hook.el
new file mode 100644
index 00000000..b6c71dd7
--- /dev/null
+++ b/tests/test-dev-fkeys--f4-make-once-hook.el
@@ -0,0 +1,115 @@
+;;; test-dev-fkeys--f4-make-once-hook.el --- Tests for cj/--f4-make-once-hook -*- lexical-binding: t -*-
+
+;;; Commentary:
+;; Tests for the one-shot `compilation-finish-functions' hook builder used by
+;; "Compile + Run" and "Clean + Rebuild" to chain a follow-up command after
+;; a successful compile. The returned lambda:
+;;
+;; - removes itself from `compilation-finish-functions' on first invocation
+;;   regardless of status (so it never lingers across compiles)
+;; - invokes THEN-FN only when the status string indicates success — i.e.
+;;   `string-prefix-p \"finished\"' matches.
+;;
+;; The status conventions come from the compile.el infrastructure: a
+;; successful compile passes \"finished\\n\", a failed compile passes
+;; something starting with \"exited\".
+
+;;; Code:
+
+(require 'ert)
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'dev-fkeys)
+
+;;; Normal Cases
+
+(ert-deftest test-dev-fkeys-make-once-hook-success-status-calls-then-fn ()
+  "Normal: status starting with 'finished' invokes THEN-FN once."
+  (let* ((called 0)
+         (hook (cj/--f4-make-once-hook (lambda () (cl-incf called)))))
+    (let ((compilation-finish-functions nil))
+      (add-hook 'compilation-finish-functions hook)
+      (funcall hook nil "finished\n"))
+    (should (= called 1))))
+
+(ert-deftest test-dev-fkeys-make-once-hook-failure-status-skips-then-fn ()
+  "Normal: status string starting with 'exited abnormally' does not invoke THEN-FN."
+  (let* ((called 0)
+         (hook (cj/--f4-make-once-hook (lambda () (cl-incf called)))))
+    (let ((compilation-finish-functions nil))
+      (add-hook 'compilation-finish-functions hook)
+      (funcall hook nil "exited abnormally with code 1\n"))
+    (should (= called 0))))
+
+(ert-deftest test-dev-fkeys-make-once-hook-success-removes-itself ()
+  "Normal: hook removes itself from `compilation-finish-functions' on success."
+  (let* ((hook (cj/--f4-make-once-hook (lambda () nil)))
+         (compilation-finish-functions (list hook)))
+    (should (memq hook compilation-finish-functions))
+    (funcall hook nil "finished\n")
+    (should-not (memq hook compilation-finish-functions))))
+
+;;; Boundary Cases
+
+(ert-deftest test-dev-fkeys-make-once-hook-failure-also-removes-itself ()
+  "Boundary: hook removes itself even on failure, so it never fires on the
+next compile. THEN-FN is not invoked, but the hook is still cleaned up."
+  (let* ((called 0)
+         (hook (cj/--f4-make-once-hook (lambda () (cl-incf called))))
+         (compilation-finish-functions (list hook)))
+    (funcall hook nil "exited abnormally with code 1\n")
+    (should (= called 0))
+    (should-not (memq hook compilation-finish-functions))))
+
+(ert-deftest test-dev-fkeys-make-once-hook-only-fires-then-fn-once ()
+  "Boundary: re-invoking the hook lambda after it self-removes does not
+re-trigger THEN-FN — the hook has been removed from the hook list and only
+external mistakes (calling the lambda directly twice) could trigger it. We
+guard against that case anyway by checking the hook removed itself, so a
+second direct funcall sees the (now-gone) hook still calls THEN-FN. This
+test documents the contract: the hook does not gate on its own state, only
+on the hook list. So the SECOND direct funcall WILL call THEN-FN. The
+guarantee in production is that `compilation-finish-functions' calls each
+hook exactly once per compile, so the practical contract is one-shot."
+  (let* ((called 0)
+         (hook (cj/--f4-make-once-hook (lambda () (cl-incf called))))
+         (compilation-finish-functions (list hook)))
+    (funcall hook nil "finished\n")
+    (funcall hook nil "finished\n")
+    (should (= called 2))))
+
+(ert-deftest test-dev-fkeys-make-once-hook-empty-status-skips-then-fn ()
+  "Boundary: empty status string does not invoke THEN-FN."
+  (let* ((called 0)
+         (hook (cj/--f4-make-once-hook (lambda () (cl-incf called)))))
+    (let ((compilation-finish-functions nil))
+      (add-hook 'compilation-finish-functions hook)
+      (funcall hook nil ""))
+    (should (= called 0))))
+
+(ert-deftest test-dev-fkeys-make-once-hook-interrupt-status-skips-then-fn ()
+  "Boundary: an 'interrupt' status (process killed) does not invoke THEN-FN."
+  (let* ((called 0)
+         (hook (cj/--f4-make-once-hook (lambda () (cl-incf called)))))
+    (let ((compilation-finish-functions nil))
+      (add-hook 'compilation-finish-functions hook)
+      (funcall hook nil "interrupt\n"))
+    (should (= called 0))))
+
+;;; Error Cases
+
+(ert-deftest test-dev-fkeys-make-once-hook-then-fn-error-still-removes-hook ()
+  "Error: if THEN-FN raises, the hook is still removed first so the
+follow-up doesn't run twice on the next compile.
+
+Components integrated:
+- `cj/--f4-make-once-hook' (the unit under test)
+- `compilation-finish-functions' (real, mutated via add-hook/remove-hook)
+- A then-fn that signals an error"
+  (let* ((hook (cj/--f4-make-once-hook (lambda () (error "boom"))))
+         (compilation-finish-functions (list hook)))
+    ;; Hook signals through the error from THEN-FN; remove-hook ran first.
+    (should-error (funcall hook nil "finished\n"))
+    (should-not (memq hook compilation-finish-functions))))
+
+(provide 'test-dev-fkeys--f4-make-once-hook)
+;;; test-dev-fkeys--f4-make-once-hook.el ends here