refactor: organize documentation structure

Russian documentation:
- Created docs/ru/ for Russian documents
- Moved 5 Russian reports to docs/ru/reports/
- Created English translations in docs/reports/

Documentation organization:
- Moved FPGA docs to docs/fpga/
- Moved BitNet/academic docs to docs/academic/
- Moved benchmarks to docs/benchmarks/
- Moved guides to docs/guides/
- Moved agent docs to docs/agents/
- Moved browser docs to docs/browser-automation/
- Moved roadmap docs to docs/roadmap/
- Created docs/misc/ for miscellaneous docs
- Removed nested docs/docs/ duplicate

New files:
- docs/INDEX.md - Documentation navigation
- docs/ru/README.md - Russian docs index
- docs/reports/TYPE_CHECKER_FIX_REPORT.md (EN)
- docs/reports/ZIG_API_UPDATE_REPORT.md (EN)
- docs/reports/PARALLEL_TESTING_REPORT.md (EN)

Co-authored-by: Ona <no-reply@ona.com>

Author: gHashTag