refactor: reorganize docs/ into clean 9-directory structure

Before: 34 directories (chaotic)
After: 9 directories (organized)

New structure:
- getting-started/ (16 docs) - Installation, tutorials, guides
- api/ (3 docs) - API reference
- architecture/ (22 docs) - System design, internals
- fpga/ (39 docs) - Hardware, BitNet, benchmarks
- research/ (39 docs) - Scientific papers, proofs
- integrations/ (78 docs) - Agents, browser, IGLA, PAS
- development/ (77 docs) - Koschei, reports, roadmap
- i18n/ (11 docs) - Russian, English translations
- archive/ (5514 docs) - Historical, book chapters

Added README.md navigation files for each directory:
- docs/README.md - Main documentation index
- docs/getting-started/README.md
- docs/api/README.md
- docs/fpga/README.md
- docs/research/README.md
- docs/integrations/README.md
- docs/development/README.md
- docs/architecture/README.md

Merged directories:
- academic + scientific + papers → research/
- koschei + reports + verdicts + roadmap → development/
- agents + browser + igla + pas + webarena → integrations/
- benchmarks + competitors → fpga/
- quickstart + guides → getting-started/
- ru + en → i18n/
- biblia + habr + misc + 3dgs + 999 + epifaneia → archive/

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

Author: gHashTag