Add configuration and logging improvements

[Copilot]

This PR improves configuration flexibility and logging initialization to support environment-based configuration and more robust log level handling.

Changes

• Configuration: Added environment variable support with viper.SetEnvPrefix("of") and viper.AutomaticEnv() for 12-factor app compliance

• Logging:

  • Extracted InitLogger() as a separate function callable after viper initialization
  • Support both string ("debug", "info") and integer log levels
  • Support both loglevel and log_level config keys for flexibility
  • Default to InfoLevel when unspecified

• Error handling: Replaced panic() with structured error logging + os.Exit(1) in P2P node initialization

• Log noise: Reduced connection summary from Info to Debug level

Example

# Now supports environment variables
export OF_LOGLEVEL=debug
export OF_WALLET_ACCOUNT=abc123
./ocf start

Dependencies

• Updated stretchr/testify to v1.11.1
• Added indirect dependencies: go-co-op/gocron/v2, jonboulle/clockwork, robfig/cron/v3

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.