Merge pull request #795 from asuc-octo/feat/helm-diff-documentation

(core) `/helm-diff` pr comment documentation

docs/src/core/infrastructure/runbooks.md

@@ -20,6 +20,23 @@
     ```sh
     k create job --from cronjob/bt-prod-datapuller-courses bt-prod-datapuller-courses-manual-01
     ```
+## Previewing Infra Changes with `/helm-diff` before deployment
+
+The `/helm-diff` command can be used in pull request comments to preview Helm changes before they are deployed. This is particularly useful when:
+
+1. Making changes to Helm chart values in `infra/app` or `infra/base`
+2. Upgrading Helm chart versions or dependencies
+3. Modifying Kubernetes resource configurations
+
+To use it:
+1. Comment `/helm-diff` on any pull request
+2. The workflow will generate a diff showing:
+   - Changes to both app and base charts
+   - Resource modifications (deployments, services, etc.)
+   - Configuration updates
+
+The diff output is formatted as collapsible sections for each resource, with a raw diff available at the bottom for debugging.
+
 
 ## Uninstall ALL development helm releases