feat: enhance error handling and configuration validation

- Added a global exception handler to log unhandled exceptions and return a generic 500 JSON response without exposing details to the client.
- Updated the configuration to validate the `DATABASE_URL` format, ensuring it starts with `sqlite://` or `postgresql://`, and log warnings for invalid formats.
- Introduced safe parsing for numeric environment variables (`HTTP_PORT`, `INIT_DATA_MAX_AGE_SECONDS`) with defaults on invalid values, including logging warnings for out-of-range values.
- Enhanced the duty schedule parser to enforce limits on the number of schedule rows and the length of full names and duty strings, raising appropriate errors when exceeded.
- Updated internationalization messages to include generic error responses for import failures and parsing issues, improving user experience.
- Added unit tests to verify the new error handling and configuration validation behaviors.

webapp/js/i18n.js

@@ -40,6 +40,7 @@ export const MESSAGES = {
     "event_type.duty": "Duty",
     "event_type.unavailable": "Unavailable",
     "event_type.vacation": "Vacation",
+    "event_type.other": "Other",
     "duty.now_on_duty": "On duty now",
     "duty.none_this_month": "No duties this month.",
     "duty.today": "Today",
@@ -96,6 +97,7 @@ export const MESSAGES = {
     "event_type.duty": "Дежурство",
     "event_type.unavailable": "Недоступен",
     "event_type.vacation": "Отпуск",
+    "event_type.other": "Другое",
     "duty.now_on_duty": "Сейчас дежурит",
     "duty.none_this_month": "В этом месяце дежурств нет.",
     "duty.today": "Сегодня",
@@ -161,10 +163,30 @@ export function getLang() {
  * @param {Record<string, string>} [params] - e.g. { time: '14:00' }
  * @returns {string}
  */
+/**
+ * Resolve event_type.* key with fallback: unknown types use event_type.duty or event_type.other.
+ * @param {'ru'|'en'} lang
+ * @param {string} key
+ * @returns {string}
+ */
+function tEventType(lang, key) {
+  const dict = MESSAGES[lang] || MESSAGES.en;
+  const enDict = MESSAGES.en;
+  let s = dict[key];
+  if (s === undefined) s = enDict[key];
+  if (s === undefined) {
+    s = dict["event_type.other"] || enDict["event_type.other"] || enDict["event_type.duty"] || key;
+  }
+  return s;
+}
+
 export function t(lang, key, params = {}) {
   const dict = MESSAGES[lang] || MESSAGES.en;
   let s = dict[key];
   if (s === undefined) s = MESSAGES.en[key];
+  if (s === undefined && key.startsWith("event_type.")) {
+    return tEventType(lang, key);
+  }
   if (s === undefined) return key;
   Object.keys(params).forEach((k) => {
     s = s.replace(new RegExp("\\{" + k + "\\}", "g"), params[k]);