feat: better sentry config sending envs

[bolinocroustibat]

Improve Sentry configuration with environment and sample rate

Adds environment and configurable sample rate to Sentry initialization.
Changes:

• Add environment parameter to Sentry initialization (defaults to "unknown" if not set)
• Add configurable SENTRY_SAMPLE_RATE for traces and profiles sampling
• Add ENVIRONMENT and SENTRY_SAMPLE_RATE to default config
  Apply changes to both app.py and metrics.py
  This enables filtering errors by environment in Sentry and allows adjusting sampling rates per environment.

[maudetes]

As discussed, we may not need this additional variable?

[bolinocroustibat]

Agreed, changed