add deprecation warning for v2 metrics endpoint (Jolokia) - not ready to merge as there is no replacement

[corporate-gadfly]

Checklist

I have:

• read the CONTRIBUTING.md document
• read and accepted the Developer Certificate of Origin document and added a Signed-off-by annotation to each of my commits
• read and accepted the AI Policy document and added Generated-by or Assisted-by annotations to each of my commits created with the help of an AI agent
• tested this code
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• documented the code
• added or modified regression test(s)
• added or modified unit test(s)

[Sharpie]

I think it is too early to add a deprecation warning when there is no replacement available for folks to start using instead.

[silug]

I think it is too early to add a deprecation warning when there is no replacement available for folks to start using instead.

@Sharpie isn't now the perfect time? We're not saying it will be removed in OpenVox 10, but it gives us permission if we're ready then.