refactor(prog): six programming-track hygiene fixes from re-review

- prog-lsp.el: rename `cj/lsp--remove-eldoc-provider' →
  `cj/lsp--remove-eldoc-provider-global' and call it once from the
  lsp-mode `:config' block instead of attaching it per-buffer via
  `lsp-managed-mode-hook'.  The previous per-buffer remove with the
  buffer-local flag raced lsp-mode's own population of the local
  hook; removing the provider from the global default before any LSP
  buffer attaches makes the absence stick.  Two existing tests
  updated to the new contract (remove-from-default + idempotent
  re-run).

- prog-webdev.el / prog-python.el: warn at load time when
  `prettier' or `pyright' is missing on PATH via
  `cj/executable-find-or-warn'.  Both modules now `(require
  'system-lib)' to expose the helper.  Missing dependencies surface
  up front instead of mid-edit at first format/LSP attach.

- keyboard-compat.el: document existing idempotence.  The hook
  install uses a named function so `add-hook' deduplicates, and the
  hook body only calls `define-key' (latest binding wins, same
  value) -- adding a comment so future readers don't re-question.

- dev-fkeys.el: add a `typescript' clause to
  `cj/--f6-test-runner-cmd-for'.  F6 now runs `npx --no-install
  vitest <path>' when vitest is on PATH, otherwise `npx --no-install
  jest <path>'.  Updates the matching test from "returns nil" to
  cover both code paths; the impl-level test now asserts the routed
  command instead of expecting a user-error.

- flycheck-config.el: build the LanguageTool wrapper path with
  `(expand-file-name "scripts/languagetool-flycheck"
  user-emacs-directory)' instead of a hardcoded `~/.emacs.d/...'.
  Survives a non-standard `user-emacs-directory'.

- latex-config.el: replace the hardcoded Zathura viewer with
  `cj/--latex-select-pdf-viewer', which walks
  `cj/--latex-pdf-viewer-candidates' (zathura → evince → okular →
  SumatraPDF → xdg-open) and falls back to "PDF Tools" when nothing
  is on PATH.  Each entry maps an executable to the matching
  TeX-view-program-list name so AUCTeX's defaults handle the
  actual viewer invocation.

3 files changed, 45 insertions, 25 deletions

diff --git a/tests/test-dev-fkeys--f6-current-file-tests-impl.el b/tests/test-dev-fkeys--f6-current-file-tests-impl.el
index 318a78db..1cf22230 100644
--- a/tests/test-dev-fkeys--f6-current-file-tests-impl.el
+++ b/tests/test-dev-fkeys--f6-current-file-tests-impl.el
@@ -105,13 +105,17 @@ just that file's tests run, not the whole module's prefix."
                    "/home/u/proj/modules/foo.el" nil)
                   :type 'user-error)))
 
-(ert-deftest test-dev-fkeys-f6-current-file-tests-impl-unsupported-language-errors ()
-  "Error: a file with no language-specific runner signals a user-error
-naming the language."
-  (cl-letf (((symbol-function 'compile) (lambda (_cmd) nil)))
-    (should-error (cj/--f6-current-file-tests-impl
-                   "/home/u/proj/src/foo.test.ts" "/home/u/proj/")
-                  :type 'user-error)))
+(ert-deftest test-dev-fkeys-f6-current-file-tests-impl-typescript-runs-jest ()
+  "TypeScript now routes to the `npx --no-install jest|vitest <path>'
+runner instead of erroring as unsupported."
+  (let ((compile-called nil))
+    (cl-letf (((symbol-function 'compile)
+               (lambda (cmd) (setq compile-called cmd)))
+              ((symbol-function 'executable-find) (lambda (_) nil)))
+      (cj/--f6-current-file-tests-impl
+       "/home/u/proj/src/foo.test.ts" "/home/u/proj/")
+      (should (stringp compile-called))
+      (should (string-match-p "jest src/foo.test.ts" compile-called)))))
 
 (ert-deftest test-dev-fkeys-f6-current-file-tests-impl-unknown-language-errors ()
   "Error: an unknown extension signals a user-error rather than running
diff --git a/tests/test-dev-fkeys--f6-test-runner-cmd-for.el b/tests/test-dev-fkeys--f6-test-runner-cmd-for.el
index 36f97548..9a552612 100644
--- a/tests/test-dev-fkeys--f6-test-runner-cmd-for.el
+++ b/tests/test-dev-fkeys--f6-test-runner-cmd-for.el
@@ -118,10 +118,25 @@ would over-match. Pass just the basename — the Makefile re-prepends
 
 ;;; Error Cases
 
-(ert-deftest test-dev-fkeys-f6-cmd-for-typescript-returns-nil ()
-  "Error: TypeScript is punted for v1 and returns nil."
-  (should (null (cj/--f6-test-runner-cmd-for
-                 'typescript t "src/foo.test.ts" "foo" "src"))))
+(ert-deftest test-dev-fkeys-f6-cmd-for-typescript-uses-jest-or-vitest ()
+  "Normal: TypeScript builds an `npx vitest|jest <path>' command.
+Picks vitest when on PATH, jest otherwise.  Falls back to jest as the
+default runner so the command shape is always inspectable -- even if
+neither tool is present, the user gets a clear runner-not-found error
+rather than a silent nil that F6's outer wrapper interprets as
+\"language unsupported.\""
+  (cl-letf (((symbol-function 'executable-find)
+             (lambda (_) nil)))
+    (should (equal
+             (cj/--f6-test-runner-cmd-for
+              'typescript t "src/foo.test.ts" "foo" "src")
+             "npx --no-install jest src/foo.test.ts")))
+  (cl-letf (((symbol-function 'executable-find)
+             (lambda (p) (when (equal p "vitest") "/usr/bin/vitest"))))
+    (should (equal
+             (cj/--f6-test-runner-cmd-for
+              'typescript t "src/foo.test.ts" "foo" "src")
+             "npx --no-install vitest src/foo.test.ts"))))
 
 (ert-deftest test-dev-fkeys-f6-cmd-for-javascript-returns-nil ()
   "Error: JavaScript is punted for v1 and returns nil."
diff --git a/tests/test-prog-lsp--add-file-watch-ignored-extras.el b/tests/test-prog-lsp--add-file-watch-ignored-extras.el
index 142cd2ea..9b71cab8 100644
--- a/tests/test-prog-lsp--add-file-watch-ignored-extras.el
+++ b/tests/test-prog-lsp--add-file-watch-ignored-extras.el
@@ -87,23 +87,24 @@
     (should-error (cj/lsp--add-file-watch-ignored-extras)
                   :type 'wrong-type-argument)))
 
-(ert-deftest test-prog-lsp--remove-eldoc-provider-removes-lsp-provider-locally ()
-  "Normal: remove lsp-mode's Eldoc provider from the buffer-local hook."
-  (with-temp-buffer
-    (setq-local eldoc-documentation-functions
-                '(lsp-eldoc-function eldoc-documentation-default))
-    (cj/lsp--remove-eldoc-provider)
+(ert-deftest test-prog-lsp--remove-eldoc-provider-global-removes-from-default ()
+  "Normal: remove lsp-mode's Eldoc provider from the global hook value.
+The per-buffer removal that this replaced raced lsp-mode's own buffer-
+local hook population; removing globally before any LSP buffer attaches
+makes the absence stick for every subsequent lsp-managed buffer."
+  (let ((eldoc-documentation-functions
+         '(lsp-eldoc-function eldoc-documentation-default)))
+    (cj/lsp--remove-eldoc-provider-global)
     (should-not (memq #'lsp-eldoc-function eldoc-documentation-functions))
     (should (memq 'eldoc-documentation-default eldoc-documentation-functions))))
 
-(ert-deftest test-prog-lsp--remove-eldoc-provider-does-not-touch-default-value ()
-  "Boundary: removing the LSP provider in one buffer leaves the default hook alone."
-  (let ((eldoc-documentation-functions '(lsp-eldoc-function)))
-    (with-temp-buffer
-      (setq-local eldoc-documentation-functions '(lsp-eldoc-function))
-      (cj/lsp--remove-eldoc-provider)
-      (should-not (memq #'lsp-eldoc-function eldoc-documentation-functions)))
-    (should (memq #'lsp-eldoc-function eldoc-documentation-functions))))
+(ert-deftest test-prog-lsp--remove-eldoc-provider-global-is-idempotent ()
+  "Boundary: re-running the removal after the provider is gone is a no-op."
+  (let ((eldoc-documentation-functions '(eldoc-documentation-default)))
+    (cj/lsp--remove-eldoc-provider-global)
+    (cj/lsp--remove-eldoc-provider-global)
+    (should (equal eldoc-documentation-functions
+                   '(eldoc-documentation-default)))))
 
 (ert-deftest test-prog-lsp--module-no-obsolete-lsp-eldoc-hook-reference ()
   "Regression: prog-lsp should not reference obsolete `lsp-eldoc-hook'."