fix: preserve cron semantics during node-cron adaptation

Preserve supported expression fields instead of stringifying them, and probe individual fields only when whole-expression validation fails. Convert unsupported syntax and weekday ranges ending in 7 while preserving legacy date/weekday rules and valid OR branches.

Add execution regressions for issue #3099 and 64 calendar boundary cases in UTC and Asia/Shanghai. Ensure timezone child tests actually run under the Node test runner.

Validation: 745 tests passed, 8 skipped; final targeted regressions passed; backend compilation passed. Differential calendar checks matched 142,360 execution timestamps.

Fixes #3099

back/shared/cronSchedule.ts

@@ -22,6 +22,7 @@ export interface CronSchedule {
 // Validation and registration repeatedly see identical rules in large snapshots.
 // Cache only immutable syntax, never dates or running tasks, and bound user input.
 const scheduleCache = new Map<string, CronSchedule>();
+const daysInMonth = [31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
 
 // Canonicalize legacy shorthand, aliases, names and numeric-start steps before
 // node-cron sees them. Extend legacy aliases explicitly; reject H and bare /N.
@@ -58,17 +59,73 @@ export function parseCronSchedule(schedule: unknown): CronSchedule {
   const expression = CronExpressionParser.parse(parts.join(' '));
   if (!expression.hasNext())
     throw new Error('Cron schedule has no next execution');
-  const normalized = expression.stringify(true).replace(/\?/g, '*').split(' ');
-  const dayCount = expression.fields.dayOfMonth.values.length;
+  let normalized = parts.map((part) => part.replace(/\?/g, '*'));
+  // cron-parser includes Sunday in stepped ranges ending in 7 even when the
+  // step does not land on 7. node-cron accepts those ranges with different days.
+  if (/(^|,)(?:\d+|[a-z]{3})-0*7\/\d+(?=,|$)/i.test(normalized[5])) {
+    normalized[5] = expression.fields.dayOfWeek.values.join(',');
+  }
+  // Most rules are already supported; only inspect individual fields on failure.
+  if (!validate(normalized.join(' '))) {
+    const fields = [
+      expression.fields.second,
+      expression.fields.minute,
+      expression.fields.hour,
+      expression.fields.dayOfMonth,
+      expression.fields.month,
+      expression.fields.dayOfWeek,
+    ];
+    normalized = normalized.map((value, index) => {
+      // Preserve supported lists, ranges and names. Expand only fields node-cron
+      // cannot consume, such as numeric/name-start steps; never compress them.
+      const probe = ['0', '0', '0', '*', '*', '*'];
+      probe[index] = value;
+      if (validate(probe.join(' '))) return value;
+      const values = fields[index].values;
+      if (index === 5 && expression.fields.dayOfWeek.nthDay) {
+        // The legacy normalizer treated *#N / ?#N as an unrestricted weekday.
+        if (values.length === 8) return '*';
+        // # applies to a single weekday; normalize its numeric spelling only.
+        return values.length === 1
+          ? `${values[0]}#${expression.fields.dayOfWeek.nthDay}`
+          : value;
+      }
+      return values.join(',');
+    });
+  }
+  const months = expression.fields.month.values;
+  // cron-parser 4 clipped dates outside a single selected month's maximum
+  // before deciding whether the day field covered the whole month.
+  const dayCount = expression.fields.dayOfMonth.values.filter(
+    (day) =>
+      months.length !== 1 ||
+      typeof day !== 'number' ||
+      day <= daysInMonth[months[0] - 1],
+  ).length;
   const weekCount = expression.fields.dayOfWeek.values.length;
+  // Preserve the legacy count-based wildcard rules, including repeated Sunday
+  // and L tokens: an ignored day field must not remain an AND constraint.
+  const weekdayPattern = [
+    ...normalized.slice(0, 3),
+    '*',
+    ...normalized.slice(4),
+  ].join(' ');
   const patterns =
-    dayCount < 31 && weekCount < 8
-      ? [
-          [...normalized.slice(0, 5), '*'].join(' '),
-          [...normalized.slice(0, 3), '*', ...normalized.slice(4)].join(' '),
-        ]
-      : [normalized.join(' ')];
-  if (!patterns.every((pattern) => validate(pattern))) {
+    weekCount === 8
+      ? [[...normalized.slice(0, 5), '*'].join(' ')]
+      : dayCount < 31
+      ? [[...normalized.slice(0, 5), '*'].join(' '), weekdayPattern]
+      : [weekdayPattern];
+  const valid = patterns.map((pattern) => validate(pattern));
+  if (patterns.length === 2 && !valid[0] && valid[1]) {
+    // A date branch can be impossible for all chosen months while the weekday
+    // branch still runs. Drop it only if its syntax is valid with any month.
+    if (validate([...normalized.slice(0, 4), '*', '*'].join(' '))) {
+      patterns.shift();
+      valid.shift();
+    }
+  }
+  if (!valid.every(Boolean)) {
     throw new Error('Unsupported cron schedule');
   }
   const parsed = {