ci: sync translations from develop to version-16-hotfix (backport #55348) (#55353)

Co-authored-by: Diptanil Saha <diptanil@frappe.io>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
fix (#55348)

.github/helper/merge_po_files.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+"""Overlay develop's .po translations onto hotfix's .po files.
+
+Called by sync_hotfix_translations.sh before `bench update-po-files`.
+Merge rules:
+  a. msgid absent from develop  → keep hotfix's existing msgstr
+  b. language not yet in hotfix → copy file as-is (bench will filter to main.pot)
+  c. msgid present in both      → use develop's msgstr
+"""
+import shutil
+from pathlib import Path
+
+from babel.messages.pofile import read_po, write_po
+
+DEVELOP = Path("/tmp/develop-po/erpnext/locale/")
+LOCALE  = Path("./apps/erpnext/erpnext/locale/")
+
+added = updated = 0
+
+for src in sorted(DEVELOP.glob("*.po")):
+    dst = LOCALE / src.name
+
+    with src.open("rb") as f:
+        dev = read_po(f)
+
+    if not dst.exists():
+        shutil.copy(src, dst)
+        added += 1
+        print(f"  [new]     {src.name}")
+        continue
+
+    with dst.open("rb") as f:
+        hf = read_po(f)
+
+    changes = 0
+    for msg in hf:
+        if msg.id and msg.id in dev and dev[msg.id].string and dev[msg.id].string != msg.string:
+            msg.string = dev[msg.id].string
+            changes += 1
+
+    if changes:
+        with dst.open("wb") as f:
+            write_po(f, hf)
+        updated += 1
+        print(f"  [updated] {src.name} ({changes} msgstr(s) from develop)")
+    else:
+        print(f"  [no-op]   {src.name}")
+
+print(f"\n{added} new language(s), {updated} updated.")