fix(org-latex): tabularx filter with lYYY column spec matching template

document.org template defines Y column type (RaggedRight + auto-width X).
Filter now computes proper column spec:
  - 1 col  → Y
  - N cols → l + (N-1)*Y  (first col natural-width, rest auto-width)

Also handles tabularx{colspec} → tabularx{\linewidth}{lYYY} (missing width fix).
Works with ltablex (loaded by template) which makes tabularx also support page breaks.

config.el

@@ -325,31 +325,41 @@ Bound to cmd+v in org-mode and markdown-mode."
 ;;; ORG MODE — LATEX EXPORT
 ;;; ============================================================
 
-;; LaTeX table export: tabular → tabularx{\linewidth}
+;; LaTeX table export: tabular → tabularx{\linewidth} with lYYY column spec.
 ;; Filter on rendered LaTeX string — no buffer modification, no recursion.
-;; Handles both cases:
-;;   \begin{tabular}{lll}          → \begin{tabularx}{\linewidth}{lll}
-;;   \begin{tabularx}{lll}         → \begin{tabularx}{\linewidth}{lll}  (missing width)
+;; Uses Y column type (defined in document.org template: RaggedRight + auto-width X).
+;; Handles:
+;;   \begin{tabular}{lll}   → \begin{tabularx}{\linewidth}{lYY}
+;;   \begin{tabularx}{lll}  → \begin{tabularx}{\linewidth}{lYY}  (missing width fix)
+(defun my/org-latex-col-to-lyyy (spec)
+  "Convert tabular column SPEC to tabularx lYYY format.
+Counts l/r/c columns; first → l, rest → Y (auto-width, defined in template)."
+  (let* ((ncols (length (replace-regexp-in-string "[^lrcLRCpP]" "" spec)))
+         (ncols (max 1 ncols)))
+    (if (= ncols 1) "Y"
+      (concat "l" (make-string (1- ncols) ?Y)))))
+
 (defun my/org-latex-fix-tabularx (table _backend _info)
-  "Convert tabular → tabularx{\\linewidth} in LaTeX table transcoder output."
+  "Convert tabular → tabularx{\\linewidth}{lYYY} in LaTeX table output."
   (when (stringp table)
-    ;; Fix tabularx with missing width (org versions that don't add \linewidth)
+    ;; Fix tabularx{colspec} missing width (some org versions omit \linewidth)
     (setq table
           (replace-regexp-in-string
            "\\\\begin{tabularx}{\\([^\\\\][^}]*\\)}"
-           "\\\\begin{tabularx}{\\\\linewidth}{\\1}"
+           (lambda (m)
+             (format "\\begin{tabularx}{\\linewidth}{%s}"
+                     (my/org-latex-col-to-lyyy (match-string 1 m))))
            table))
-    ;; Convert plain tabular to tabularx
+    ;; Convert tabular{colspec} → tabularx{\linewidth}{lYYY}
     (setq table
           (replace-regexp-in-string
            "\\\\begin{tabular}{\\([^}]*\\)}"
-           "\\\\begin{tabularx}{\\\\linewidth}{\\1}"
+           (lambda (m)
+             (format "\\begin{tabularx}{\\linewidth}{%s}"
+                     (my/org-latex-col-to-lyyy (match-string 1 m))))
            table))
     (setq table
-          (replace-regexp-in-string
-           "\\\\end{tabular}"
-           "\\\\end{tabularx}"
-           table)))
+          (replace-regexp-in-string "\\\\end{tabular}" "\\\\end{tabularx}" table)))
   table)
 
 ;; Register filter on ox-latex load AND ensure it via a pre-processing hook