feat(cron): configurable failure alerts for repeated job errors (openclaw#24789) thanks @0xbrak

Verified:
- pnpm install --frozen-lockfile
- pnpm check
- pnpm test -- --run src/cron/service.failure-alert.test.ts src/cli/cron-cli.test.ts src/gateway/protocol/cron-validators.test.ts

Co-authored-by: 0xbrak <181251288+0xbrak@users.noreply.github.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

src/gateway/protocol/schema/cron.ts

@@ -187,6 +187,16 @@ export const CronDeliveryPatchSchema = Type.Object(
   { additionalProperties: false },
 );
 
+export const CronFailureAlertSchema = Type.Object(
+  {
+    after: Type.Optional(Type.Integer({ minimum: 1 })),
+    channel: Type.Optional(Type.Union([Type.Literal("last"), NonEmptyString])),
+    to: Type.Optional(Type.String()),
+    cooldownMs: Type.Optional(Type.Integer({ minimum: 0 })),
+  },
+  { additionalProperties: false },
+);
+
 export const CronJobStateSchema = Type.Object(
   {
     nextRunAtMs: Type.Optional(Type.Integer({ minimum: 0 })),
@@ -200,6 +210,7 @@ export const CronJobStateSchema = Type.Object(
     lastDelivered: Type.Optional(Type.Boolean()),
     lastDeliveryStatus: Type.Optional(CronDeliveryStatusSchema),
     lastDeliveryError: Type.Optional(Type.String()),
+    lastFailureAlertAtMs: Type.Optional(Type.Integer({ minimum: 0 })),
   },
   { additionalProperties: false },
 );
@@ -220,6 +231,7 @@ export const CronJobSchema = Type.Object(
     wakeMode: CronWakeModeSchema,
     payload: CronPayloadSchema,
     delivery: Type.Optional(CronDeliverySchema),
+    failureAlert: Type.Optional(Type.Union([Type.Literal(false), CronFailureAlertSchema])),
     state: CronJobStateSchema,
   },
   { additionalProperties: false },
@@ -249,6 +261,7 @@ export const CronAddParamsSchema = Type.Object(
     wakeMode: CronWakeModeSchema,
     payload: CronPayloadSchema,
     delivery: Type.Optional(CronDeliverySchema),
+    failureAlert: Type.Optional(Type.Union([Type.Literal(false), CronFailureAlertSchema])),
   },
   { additionalProperties: false },
 );
@@ -262,6 +275,7 @@ export const CronJobPatchSchema = Type.Object(
     wakeMode: Type.Optional(CronWakeModeSchema),
     payload: Type.Optional(CronPayloadPatchSchema),
     delivery: Type.Optional(CronDeliveryPatchSchema),
+    failureAlert: Type.Optional(Type.Union([Type.Literal(false), CronFailureAlertSchema])),
     state: Type.Optional(Type.Partial(CronJobStateSchema)),
   },
   { additionalProperties: false },