Move API Reference files (Step 4)

Moved 4 files to api-reference/:
- api/view-helpers-api.md → api-reference/view-helpers-api.md
- api/javascript-api.md → api-reference/javascript-api.md
- api/redux-store-api.md → api-reference/redux-store-api.md
- additional-details/generator-details.md → api-reference/generator-details.md

Note: configuration.md already moved to api-reference in Step 2.

Total in api-reference: 5 files (reference docs for view helpers, JS API,
Redux, configuration options, and generator flags).

Part of IA redesign Phase 2, Step 4.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: ihabadham