Improve weather module error messages

[RAprogramm]

Problem

Weather module shows generic 'Internal server error' without context, making debugging impossible.

Solution

• Add HTTP status code checking before JSON parsing
• Provide specific error messages for different failures:
  • 401: Invalid API key
  • 404: Location not found
  • 429: Rate limit exceeded
  • 500+: Server errors
  • Network: Timeout/connection errors

Status

Already implemented in commit 1297816 but needs proper PR workflow.

Closes #86