docs: Improve CLI documentation UX per review feedback

Addresses review comments on PR #4425:

1. Unified all <hfoptions> IDs to 'trainers' (5 sections)
   - Enables persistent trainer selection across all documentation sections
   - Improved user experience when navigating between examples

2. Consolidated inline/config file options (12 pairs → 12 single options)
   - Merged separate "inline" and "w/ config file" options
   - Used "Or with config file:" pattern for clarity
   - Applied to Sections 3 (Scaling) and 4 (Accelerate Config)

Result: 30 balanced options (6 trainers × 5 sections) with improved navigation

Author: behroozazarkhalili