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.

1 files changed, 32 insertions, 1 deletions

diff --git a/modules/latex-config.el b/modules/latex-config.el
index bb4cf510..a0af2a1a 100644
--- a/modules/latex-config.el
+++ b/modules/latex-config.el
@@ -15,6 +15,37 @@
 ;;
 ;;; Code:
 
+;; ----------------------------- PDF Viewer Selection --------------------------
+;;
+;; Pick whichever PDF viewer is available rather than hard-coding Zathura.
+;; The selected viewer is pushed onto `TeX-view-program-selection' for
+;; output-pdf so `C-c C-v' opens the compiled PDF.
+
+(defconst cj/--latex-pdf-viewer-candidates
+  ;; (PROGRAM . TeX-VIEWER-NAME) in preference order.  TeX-view-program-list
+  ;; has built-in entries for "Zathura", "Evince", "Okular", "Skim",
+  ;; "PDF Tools", and platform openers; we match against those names.
+  '(("zathura"     . "Zathura")
+    ("evince"      . "Evince")
+    ("okular"      . "Okular")
+    ("SumatraPDF"  . "Sumatra PDF")
+    ("xdg-open"    . "xdg-open"))
+  "Ordered (EXECUTABLE . TEX-VIEWER-NAME) pairs for PDF preview selection.")
+
+(defvar TeX-view-program-selection)
+(declare-function pdf-view-mode "pdf-view")
+
+(defun cj/--latex-select-pdf-viewer ()
+  "Push the first available external PDF viewer onto `TeX-view-program-selection'.
+Falls back to PDF Tools when no external viewer is on PATH.  The new
+selection is consed onto the head of the alist so it wins over any
+default.  Idempotent: re-running picks the same viewer."
+  (let* ((found (cl-find-if (lambda (entry)
+                              (executable-find (car entry)))
+                            cj/--latex-pdf-viewer-candidates))
+         (viewer-name (if found (cdr found) "PDF Tools")))
+    (push (list 'output-pdf viewer-name) TeX-view-program-selection)))
+
 ;; ----------------------------- Auctex And Related ----------------------------
 
 (use-package tex
@@ -25,7 +56,7 @@
   (LaTeX-mode    . (lambda () (TeX-fold-mode 1)))                    ; automatically activate TeX-fold-mode.
   (LaTeX-mode    . flyspell-mode)                               ; turn on flyspell-mode by default
   (LaTeX-mode    . TeX-PDF-mode)
-  (LaTeX-mode . (lambda () (push (list 'output-pdf "Zathura") TeX-view-program-selection)))
+  (LaTeX-mode . cj/--latex-select-pdf-viewer)
   :mode
   ("\\.tex\\'" . latex-mode)
   :config