[Task]: [Platform API] Master issue to track Platform API bugs and improvements

Description

Master (parent) issue to track the set of Platform API issues currently affecting several areas of the product. Each concrete problem is filed as its own sub-issue under this one, so the whole set can be tracked, prioritised and released together instead of being scattered across unrelated issues.

This issue itself is a tracker. No code changes are made against it directly. It stays open until every sub-issue below is closed.

Scope

Anything owned by platform-api/:

• REST API contract (platform-api/src/resources/openapi.yaml) — request/response shapes, parameters, status codes, error codes
• Handler / service / repository layers, including validation and error handling
• Authentication, authorisation and OAuth2 scope enforcement
• Multi-tenant (organization) scoping and creator-scoped resources
• Database schemas and migrations owned by Platform API
• Events published to / consumed from the gateway and portals, and cross-component consistency (gateway, api-portal, ai-workspace, CLI) where the root cause sits in Platform API

Out of scope: issues whose root cause is in the Gateway, Developer Portal, AI Workspace or CLI, those are tracked under their own areas and only linked from here when a Platform API change is required.

How to use this issue

1. File each concrete problem as a separate issue using the standard Bug / Improvement / Task template, with Area/Platform-API and the relevant Aspect/* labels.
2. Add it as a sub-issue of this issue (Create sub-issue → Add existing issue), so it appears in the checklist automatically.
3. Keep the affected area and reproduction details in the sub-issue, not here, this issue only carries the roll-up view.

Sub-issues

Tracked automatically in the sub-issue list. Grouped view for convenience:

• API contract / OpenAPI spec consistency
• Validation and error responses
• Authentication, authorisation and scopes
• Data layer and schema
• Cross-component consistency (gateway / portals / CLI)

(Replace the placeholders above with links to the actual sub-issues as they are created.)

Definition of done

• Every sub-issue is closed or explicitly moved out of scope with a reason.
• Fixes that change the REST API contract are reflected in openapi.yaml, the generated portal/CLI types, and the relevant tests.