build(deps): update kong to v3.9

[rsdmike]

No description provided.

[Copilot]

Pull request overview

Updates the local/dev deployment to run on Kong 3.9 and aligns the declarative configuration with Kong 3.x expectations.

Changes:

• Bump Kong Docker image from kong:3.1 to kong:3.9.
• Update kong.yaml declarative config _format_version to "3.0" and mark the two device power routes as regex paths (via ~ prefix).
• Clean up minor trailing whitespace/formatting in docker-compose.yml.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
kong.yaml	Updates declarative config format version and adjusts route path syntax for Kong 3.x (regex paths).
docker-compose.yml	Bumps Kong container image to 3.9 and normalizes whitespace.

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