Multiple response fields widened from int32 to int64; Agent/Cluster field types corrected

Several categories of changes are present in this diff:

• int32 → int64 on id, project_id, and pipeline_id fields across many CI/CD, pipeline, environment, runner, and deployment response schemas. Strictly speaking this is a widening (larger value range), but strongly-typed clients that generated code from int32 may overflow or need recompilation.
• type: string → type: integer (int64) for id, agent_id, and created_by_user_id in API_Entities_Clusters_AgentTokenBasic, API_Entities_Clusters_AgentToken, API_Entities_Clusters_AgentTokenWithToken, and API_Entities_Clusters_Agent. Any client that parsed these fields as strings will break.
• is_receptive in API_Entities_Clusters_Agent changed from type: string to type: boolean — string-parsing clients will break.
• created_at / last_used_at in Agent/Token schemas gained format: date-time (additive but narrows expected format).
• API_Entities_DiscoveredClusters fields groups and projects changed from type: string to type: object — clients treating these as strings will break.