Cron: normalize cron.add inputs + align channels (#256)

* fix: harden cron add and align channels

* fix: keep cron tool id params

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Co-authored-by: Peter Steinberger <steipete@gmail.com>

src/gateway/protocol/schema.ts

@@ -635,6 +635,8 @@ export const CronPayloadSchema = Type.Union([
           Type.Literal("telegram"),
           Type.Literal("discord"),
           Type.Literal("slack"),
+          Type.Literal("signal"),
+          Type.Literal("imessage"),
         ]),
       ),
       to: Type.Optional(Type.String()),