Add consistent metric labels and increase coverage

[robertocarlous]

Body:

Existing metrics lack important dimensions. Add labels for env, route, status_code and instrument request latency, background job outcomes, and external service errors.

Acceptance Criteria:

• Key metrics include env and route labels.
• Endpoints export request latency and request count metrics.
• Background jobs expose success/failure counters.

[dotunv]

I am interested to solve this issue for you

[grantfox-oss]

🦊 GrantFox — @dotunv has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #148)
2. Your PR will be reviewed by the Neurowealth maintainers

Good luck! Track your progress on GrantFox.