Fix WasmAgent/wasmagent-protocol#120 (Establish AEP schema scaffolding: schemas/index.json registry, schemas/aep/ direct

[telleroutlook]

Auto-filed as sub-issue of #120 (Establish AEP schema scaffolding: schemas/index.json registry, schemas/aep/ directory, and valid/invalid fixture conventions).

Fix #120 (Establish AEP schema scaffolding: schemas/index.json registry, schemas/aep/ directory, and valid/invalid fixture conventions): implement changes in package seed

Files to change:

• valid
• invalid

Acceptance criteria

• go build ./... passes
• The specific changes described above are implemented
• No unrelated files touched

[telleroutlook]

🤖 Patrol bot split proposal

This issue appears to contain multiple independent pieces of work. Proposed sub-issues:

1. Create schemas/aep/ directory structure with valid/invalid fixture subdirectories for AEP schema testing
2. Create schemas/index.json registry for AEP schema discovery and versioning
3. Clarify and resolve package seed reference in AEP scaffolding or remove if not applicable to protocol repo

If you agree, close this issue and open the sub-issues above. If the work is genuinely a single unit, remove the needs-split label.