browser/openspec/changes/implement-platform-core-domain/proposal.md

Why

The platform backend currently has architecture contracts and a health endpoint, but the core platform resources are only described in markdown. This change turns those contracts into typed, validated Go domain foundations so later API, run, frontend, and plugin work can depend on stable platform behavior.

What Changes

• Add typed platform domain resources for users, game management plugins, server instances, AI providers, run endpoints, jobs, artifacts, log streams, and audit events.
• Add DTO and model contracts for those resources in their required directories.
• Add repository interfaces plus an in-memory repository implementation suitable for unit tests and early service wiring.
• Add service interfaces and implementations for core create/list/get workflows and lifecycle-safe state changes.
• Add validators for identity, enum values, plugin-to-server relationships, run capability compatibility, AI provider redaction constraints, job idempotency, artifact metadata, log stream cursors, and audit summaries.
• Extend route catalog documentation with the core resource contract surface, without implementing full HTTP handlers in this change.

Capabilities

New Capabilities

• platform-core-domain: Typed backend domain, DTO, model, repository, service, validation, and route-contract foundations for core platform resources.

Modified Capabilities

• None.

Impact

• Affects platform/ only.
• Adds Go packages under platform/domain, platform/dto, platform/model, platform/repo, platform/service, and platform/validator.
• Updates platform/api/routes.md and platform markdown contracts where needed to reflect the implemented route contract surface.
• Adds focused platform unit tests for validators, repository behavior, service behavior, and model mappings.
• Does not add billing, cloud host sales, plugin-to-run direct access, raw AI key exposure, or full API handler behavior.