feat(console): add GET/PUT tenant YAML API endpoint and PR template

[GatewayJ]

Type of Change

• New Feature
• Bug Fix
• Documentation
• Performance Improvement
• Test/CI
• Refactor
• Other:

Related Issues

N/A

Summary of Changes

Add GET/PUT /api/v1/namespaces/{namespace}/tenants/{name}/yaml API endpoints for reading and editing the full Tenant CR as YAML, similar to the MinIO operator's tenant YAML feature.

• GET: Returns the complete Tenant CR serialized as YAML with managedFields stripped for readability.
• PUT: Accepts edited YAML, validates name/namespace match and pool uniqueness, then safely updates only spec, labels, annotations, and finalizers while preserving resourceVersion and immutable metadata.
• Model: New TenantYAML struct ({ yaml: string }).
• OpenAPI: Documentation stubs added for both endpoints.
• AGENTS.md: Added global and .github/ scoped agent instructions with rule precedence, PR baseline, and security rules.
• PR Template: Added .github/pull_request_template.md following RustFS project conventions.
• Prettier: Applied formatting to existing console-web files (no functional changes).

Checklist

• I have read and followed the CONTRIBUTING.md guidelines
• Passed make pre-commit (fmt-check + clippy + test + console-lint + console-fmt-check)
• Added/updated necessary tests
• Documentation updated (if needed)
• CHANGELOG.md updated under [Unreleased] (if user-visible change)
• CI/CD passed (if applicable)

Impact

• Breaking change (CRD/API compatibility)
• Requires doc/config/deployment update
• Other impact:

Verification

make pre-commit
# Test the new endpoint (after deploying):
# GET:
curl -b cookies.txt http://localhost:9090/api/v1/namespaces/rustfs-system/tenants/example-tenant/yaml
# PUT:
curl -b cookies.txt -X PUT http://localhost:9090/api/v1/namespaces/rustfs-system/tenants/example-tenant/yaml \
  -H "Content-Type: application/json" \
  -d '{"yaml": "..."}'

Additional Notes

The PUT endpoint follows the same safety pattern as the MinIO operator: it fetches the current Tenant from the cluster (preserving resourceVersion), then only overwrites spec, labels, annotations, and finalizers from the user-provided YAML. This prevents accidental modification of immutable metadata fields.

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Thank you for your contribution! Please ensure your PR follows the community standards (CODE_OF_CONDUCT.md) and sign the CLA if this is your first contribution.