chore: update firewall image to 2.9.8

[socket-release-bot]

Updates deployment defaults to the published Socket Firewall image 2.9.8 and bumps the Helm chart patch version.

Image: socketdev/socket-registry-firewall:2.9.8
Release run

Manual review is required before merging:

• Review the release changes for configuration or behavioral changes.
• Update deployment documentation and migration examples where needed.
• Check the Helm chart version and CloudFormation defaults, including other pending version PRs.

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Note

Low Risk
Version-pin and documentation-only changes; runtime behavior depends on the 2.9.8 image release, which should be reviewed per the PR checklist before merge.

Overview
Bumps default deployment pins for socketdev/socket-registry-firewall from 2.9.3 → 2.9.8 and the Helm chart from 0.11.7 → 0.11.8 (Chart.yaml version and appVersion).

The same image tag and chart version defaults are updated in Helm (values.yaml, README.md), CloudFormation EKS (firewall-eks.yaml parameters ChartVersion / FirewallImageTag, example dns-override.values.yaml, and cloudformation/README.md docs). No template logic or behavioral config changes—only version strings and documentation that describe those defaults.

^{Reviewed by Cursor Bugbot for commit 17846b9. Configure here.}