Summary

• Fixed the issue where parallel configuration values were completely ignored
• Implemented proper config file support for the parallel option

Problem

The parallel field existed in config files but was never actually used. The application always used CLI's default value (10) regardless of config settings.

# This was ignored:
defaults:
  parallel: 50

Solution

• Added get_parallel() method to Config struct (follows same pattern as get_timeout())
• Added parallel field to ClusterDefaults struct for cluster-specific settings
• Detect if user explicitly specified -p/--parallel in CLI arguments
• Use config value when CLI option is not explicitly provided

Priority Order

1. CLI option (if explicitly specified with -p or --parallel)
2. Cluster-specific config (clusters.<name>.parallel)
3. Global defaults config (defaults.parallel)
4. CLI default value (10)

Usage Examples

# Global default
defaults:
  parallel: 50

# Cluster-specific override
clusters:
  production:
    nodes: [...]
    parallel: 100  # Use up to 100 parallel connections for production
  dev:
    nodes: [...]
    parallel: 5    # Limit to 5 for dev environment

# Uses config value (50 from defaults or cluster-specific)
bssh -c production "uptime"

# Overrides config with explicit CLI value
bssh -c production -p 200 "uptime"

Test Plan

• Code builds successfully
• Clippy checks pass
• Code formatted with cargo fmt
• Manual testing with config files
• Verify CLI override still works
• Verify cluster-specific parallel values work