i18n: voci .po per le 3 nuove stringhe del lotto B2, test EN reso significativo

Aggiunte a mano in coda a it/en messages.po (nessuna rigenerazione):
"Sessione scaduta: effettua nuovamente l'accesso." (#12/#25),
"Ricetta non assegnata a questa stazione" (#24), "Codice non valido" (#37.4).

test_admin_stations_inline_js_is_valid_in_english (#37.5): i .mo sono
gitignored e compilati solo in Docker, non in questo run - impostare
session["language"]="en" da solo non aveva alcun effetto e il test passava
senza esercitare il bug EN reale. Ora patcha jinja_env.globals["_"] con la
traduzione nota per quella stringa, verificato che fallisca davvero sul
codice pre-fix (ripristinato subito dopo) prima di lasciarlo verde.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/frontend/flask_app/tests/test_template_js_syntax.py

@@ -197,7 +197,9 @@ def test_admin_stations_inline_js_is_valid(logged_in_client, mock_admin_api):
     _check_alpine_attributes(html, "/admin/stations")
 
 
-def test_admin_stations_inline_js_is_valid_in_english(logged_in_client, mock_admin_api):
+def test_admin_stations_inline_js_is_valid_in_english(
+    logged_in_client, mock_admin_api, flask_app,
+):
     """gitea#37.5: the EN catalog is where this page's apostrophe actually is.
 
     translations/en/LC_MESSAGES/messages.po: msgid "Azzera le ricette della
@@ -205,7 +207,25 @@ def test_admin_stations_inline_js_is_valid_in_english(logged_in_client, mock_adm
     The IT source string has no apostrophe, so test_admin_stations_inline_js_is_valid
     (IT-only) would never have caught this - #37.5's own TEST note calls out
     the EN render specifically.
+
+    The .mo catalogs are gitignored and compiled only at Docker build time
+    (compile_translations.py) - not part of this test run - so setting
+    session["language"] = "en" alone has no effect here: flask_babel falls
+    back to the (Italian) msgid with no compiled catalog to translate from.
+    The Jinja "_" global is patched directly instead, standing in for what a
+    compiled EN catalog would return for this one string; everything else
+    round-trips unchanged, same as gettext's own fallback.
     """
+    EN_TRANSLATIONS = {
+        "Azzera le ricette della stazione": "Clear the station's recipes",
+    }
+
+    def fake_gettext(msgid, **kwargs):
+        text = EN_TRANSLATIONS.get(msgid, msgid)
+        return text % kwargs if kwargs else text
+
+    flask_app.jinja_env.globals["_"] = fake_gettext
+
     mock_admin_api.get.side_effect = [
         [{
             "id": 1, "code": "ST-DEFAULT", "name": "Default Station",
@@ -215,13 +235,18 @@ def test_admin_stations_inline_js_is_valid_in_english(logged_in_client, mock_adm
         [{"id": 1, "code": "DEMO-001", "name": "Demo Recipe", "active": True}],
     ]
 
-    with logged_in_client.session_transaction() as sess:
-        sess["language"] = "en"
     resp = logged_in_client.get("/admin/stations")
     assert resp.status_code == 200, resp.data[:300]
 
     html = resp.data.decode("utf-8")
+    # The fix (#37.5) is exactly why the apostrophe shows up escaped
+    # (tojson_attr) rather than literal - that is what keeps it from
+    # breaking the surrounding JS string.
     assert "station" in html.lower(), "sanity check: the EN string did render"
+    assert "station\\u0027s recipes" in html or "station's recipes" in html, (
+        "expected the EN string's apostrophe to reach the page only as an "
+        "escaped token (tojson_attr), not literally"
+    )
 
     scripts = _INLINE_SCRIPT_RX.findall(html)
     for i, body in enumerate(scripts):