fix: add server name validation and clean invalid data before migration 009 (#591)

## Summary

This PR adds two important improvements to ensure data integrity:

1. **Adds server name format validation at the API layer** to match the
database constraint from migration 008
2. **Includes migration 008 to clean up invalid data** before applying
strict constraints in migration 009

## Changes

### Server Name Validation
- Enforces validation at the API layer matching the database constraint
- **Namespace pattern**: `[a-zA-Z0-9][a-zA-Z0-9.-]*[a-zA-Z0-9]` 
  - Must start and end with alphanumeric characters
  - Can contain dots and hyphens in the middle
- **Name pattern**: `[a-zA-Z0-9][a-zA-Z0-9._-]*[a-zA-Z0-9]`
  - Must start and end with alphanumeric characters  
  - Can contain dots, underscores, and hyphens in the middle
- Provides clear, user-friendly error messages indicating which part is
invalid
- Uses DRY approach with composed regex patterns

### Migration 008: Data Cleanup
- Removes servers with invalid names or empty versions (5 servers
affected in production)
- Fixes invalid status values by setting them to 'active' (1 server
affected)
- Removes duplicate name+version combinations
- Includes comprehensive safety checks to prevent accidental data loss
- Must run before migration 009 which adds strict constraints

## Testing
- All validator tests pass
- Migration includes safety checks that match production data
- CI verification included

---------

Co-authored-by: Claude <noreply@anthropic.com>

go.mod

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 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
 	github.com/jackc/puddle/v2 v2.2.2 // indirect
+	github.com/lib/pq v1.10.9 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect