Comprehensive User-First Documentation Overhaul

[abdoruzaqi]

This PR implements a full documentation overhaul for FlexiRule, prioritizing the end-user experience.

Key changes:

1. New Structure: Moved from a deeply nested technical structure to a flat, intuitive hierarchy under content/en/:
   • getting-started/: Onboarding and quick start.
   • using-the-builder/: Interface and navigation guides.
   • core-actions/: Simplified, page-by-page guides for all 13 logic nodes.
   • advanced-reference/: Technical specs and architecture for developers.
2. User-First Content: All action pages have been rewritten to explain what a node does and how to configure it in the UI, using real-world ERPNext examples. Technical jargon has been removed or moved to the reference section.
3. Cleanup: Removed the old docs/ directory and updated the landing page links.
4. Hugo Optimization: Maintained clean Markdown and standardized front matter weights.

Verified structural integrity and internal link resolution via automated path updates.

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PR created automatically by Jules for task 13568299900737258379 started by @abdoruzaqi

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