test(cli): add comprehensive validation coverage for run command

Add unit tests covering all validation paths in the run command including:
- Session ID validation (empty, invalid UUID, conflicts)
- Provider and API key validation
- Autonomous mode constraints (workspace, timeout, mode)
- Output format validation
- stdin stream mode validation
- Consecutive mistake limit validation
- Reasoning effort validation
- Workspace and prompt file validation

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: taltas