refactor: remove realtime.zod.ts and add discovery.zod.ts with comprehensive schemas and tests

- Deleted the existing realtime.zod.ts file containing schemas for realtime events, subscriptions, and presence.
- Introduced discovery.zod.ts to define schemas for API capabilities, routes, and discovery responses.
- Added extensive tests for the new discovery schemas to ensure validation and default values.
- Created realtime.zod.ts with schemas for transport protocols, event types, subscriptions, presence, and realtime events.
- Implemented tests for the new realtime schemas to validate various scenarios and edge cases.

Author: hotlong

…ckages/spec/src/system/discovery.test.ts packages/spec/src/api/discovery.test.tspackages/spec/src/system/discovery.test.ts renamed to packages/spec/src/api/discovery.test.ts packages/spec/src/system/discovery.test.ts renamed to packages/spec/src/api/discovery.test.ts

@@ -8,3 +8,5 @@
 
 export * from './contract.zod';
 export * from './endpoint.zod';
+export * from './discovery.zod';
+export * from './realtime.zod';

packages/spec/src/system/discovery.zod.ts packages/spec/src/api/discovery.zod.tspackages/spec/src/system/discovery.zod.ts renamed to packages/spec/src/api/discovery.zod.ts

@@ -10,7 +10,6 @@
 
 export * from './manifest.zod';
 export * from './datasource.zod';
-export * from './api.zod';
 export * from './identity.zod';
 export * from './auth.zod';
 export * from './auth-protocol';
@@ -24,9 +23,7 @@ export * from './license.zod';
 export * from './webhook.zod';
 export * from './translation.zod';
 export * from './driver.zod';
-export * from './discovery.zod';
 export * from './plugin.zod';
-export * from './realtime.zod';
 export * from './events.zod';
 export * from './job.zod';
 export * from './constants';