[Config] Make resolve_sequence_commands() work without device_name parameter

[mischadiehm]

Context

During the pypi-support branch work, tests were written that called resolve_sequence_commands("seq") without the required device_name parameter. The method signature requires a device name to resolve vendor-specific sequences.

Identified in PR for pypi-support branch merge.

Current State

• resolve_sequence_commands(sequence_name, device_name) requires both parameters
• Global sequences don't need device context to resolve
• Current implementation always requires device_name even when looking up global sequences

Desired State

Make device_name optional for resolving global sequences:

def resolve_sequence_commands(
    self, 
    sequence_name: str, 
    device_name: str | None = None
) -> list[str] | None:
    """
    Resolve a sequence name to its commands.
    
    Args:
        sequence_name: Name of the sequence to resolve
        device_name: Optional device name for vendor/device-specific resolution
        
    Returns:
        List of commands if found, None otherwise
        
    Resolution order:
        1. Global sequences (no device_name needed)
        2. Vendor sequences (requires device_name for device_type lookup)
        3. Device sequences (requires device_name)
    """

Implementation Notes

• Global sequences should be resolvable without device context
• When device_name is None, only check global sequences
• When device_name is provided, check vendor and device sequences too
• Maintain backwards compatibility with existing callers

Files Likely Affected

• src/network_toolkit/config.py - Modify resolve_sequence_commands signature
• src/network_toolkit/common/sequence_manager.py - May need updates
• tests/test_config.py - Add tests for optional device_name

Acceptance Criteria

• Global sequences resolvable without device_name
• Existing callers with device_name still work
• Clear error handling when device_name needed but not provided
• Tests cover both with and without device_name scenarios

Related

• pypi-support branch merge PR