release.yml: make locale validation fail on a glob miss

The check globbed .release/DandersFrames/Locales/*.lua with no nullglob, so an
unmatched pattern stayed literal, grep errored on the missing file, ERRORS stayed
0, and the step printed "All locale files validated OK" and exited 0. The guard
could not tell "no problems" from "wrong path" — poor for a check whose whole job
is catching broken locales, and newly dangerous now the addon layout can move.

Now sets nullglob, counts the matches, and fails with a specific error when the
count is zero.

Also swaps grep -P for -E. The pattern uses no PCRE syntax, and -P is unavailable
in some environments ("supports only unibyte and UTF-8 locales"). Combined with
the existing 2>/dev/null, a grep that cannot run reads as "file is clean" — the
same silent pass. Verified -E matches all four alternatives identically.

Author: mergetest

.github/workflows/release.yml

@@ -89,10 +89,27 @@ jobs:
       - name: Validate locale files
         if: steps.guard.outputs.skip != 'true'
         run: |
+          # ☠ A glob that matches nothing must FAIL, not pass silently.
+          # Without nullglob an unmatched pattern stays literal, grep errors on the
+          # missing file, ERRORS stays 0, and this step prints "validated OK" while
+          # checking nothing — so the guard cannot tell "no problems" from "wrong
+          # path". That matters now the addon layout can move (12.1 container reorg).
+          shopt -s nullglob
+          FILES=(.release/DandersFrames/Locales/*.lua)
+          if [ ${#FILES[@]} -eq 0 ]; then
+            echo "::error::No locale files matched .release/DandersFrames/Locales/*.lua — the packaged layout changed and this check is validating nothing. Fix the path."
+            exit 1
+          fi
+          echo "Validating ${#FILES[@]} locale file(s)"
+
           ERRORS=0
-          for f in .release/DandersFrames/Locales/*.lua; do
-            # Check for CurseForge API error responses injected as raw text
-            if grep -qP '^error code:|^<!DOCTYPE|^<html|^\{"error' "$f" 2>/dev/null; then
+          for f in "${FILES[@]}"; do
+            # Check for CurseForge API error responses injected as raw text.
+            # -E, not -P: the pattern needs no PCRE, and -P is unavailable in some
+            # environments ("supports only unibyte and UTF-8 locales"). Paired with
+            # 2>/dev/null, a grep that fails to run reads as "file is clean" — the
+            # same silent pass the nullglob guard above exists to prevent.
+            if grep -qE '^error code:|^<!DOCTYPE|^<html|^\{"error' "$f" 2>/dev/null; then
               echo "::error::Locale file contains API error response: $(basename $f)"
               head -5 "$f"
               ERRORS=$((ERRORS + 1))