[docs][MCP] Document simplified ingress for Retool 4.0.7+

[arnold-retool]

Summary

• document that Retool 4.0.7+ can route /mcp, OAuth discovery, and normal application traffic through the main Retool Service on port 3000
• document the required backend setting MCP_SERVICE_INGRESS_DOMAIN=http://<fullname>-mcp:4010
• retain the explicit 3001/4010 path mapping for Retool versions before 4.0.7

Testing

• helm lint charts/retool
• helm lint charts/retool -f charts/retool/ci/test-mcp-enabled-option.yaml
• rendered the simplified setup with the MCP-specific Ingress and HTTPRoute rules disabled
• verified the backend receives MCP_SERVICE_INGRESS_DOMAIN and no public /mcp path is rendered
• verified values.yaml and charts/retool/values.yaml remain identical
• git diff --check

[greptile-apps]

Confidence Score: 4/5

Safe to merge for the documentation content itself, but the intended chart version bump to 6.11.13 was not applied.

The comment changes are accurate and self-contained. The only gap is that Chart.yaml still carries version 6.11.12 despite the PR description explicitly listing a version bump to 6.11.13 as one of the changes — that omission should be resolved before merging so chart consumers pick up the new release.

charts/retool/Chart.yaml — version field needs to be incremented to 6.11.13

Important Files Changed

Filename	Overview
charts/retool/values.yaml	Comment block updated to document simplified ingress for Retool 4.0.7+, including MCP_SERVICE_INGRESS_DOMAIN env var and backward-compat note for older versions; functionally identical to values.yaml at repo root
values.yaml	Identical comment change to charts/retool/values.yaml, keeping the two files in sync as expected

_{Reviews (2): Last reviewed commit: "[docs][MCP] Keep chart version unchanged" | Re-trigger Greptile}

[ryanartecona]

I know CI will complain at you but you don't need to bump the patch version for this PR if it will only be a purely comment change