fix(controlplane): render current year in email template footers

[mekilis]

Summary

• Inject the current calendar year into system email templates instead of hardcoding 2024.
• Covers verify-email, organisation invite, reset-password, and endpoint-update footers.

Test plan

• go test ./internal/email/...
• Trigger a verify-email (or invite) send and confirm the footer shows the current year

[cursor]

Current version of PR was reviewed by /review-bugbot on Jul 20, 17:32 GMT+1. It flagged 0 findings.

^{Bugbot on commit f4b4bc1 is skipped.}

[linear]

PDE-932

[cursor]

Current version of PR was reviewed by /review-bugbot on Jul 20, 17:32 GMT+1. It flagged 0 findings.

^{Bugbot on commit dcc6de7 is skipped.}