docs: reorganize into en/ and bg/ subfolders with numbered indices

- New docs/index.md with language selector
- docs/en/ — 01-getting-started, 02-architecture, 03-ai-integration,
  04-api-reference, 05-user-guide, 06-roadmap
- docs/bg/ — same structure in Bulgarian
- Root README.md trimmed to quick-start + links to docs/
- Removed old flat docs/ files (ARCHITECTURE.md, AI_FIRST.md, etc.)
- Added swap!/reset! examples to getting-started guides

docs/en/index.md

@@ -0,0 +1,36 @@
+
+[← Back to Index](index.md)
+
+---
+
+# Clojure/Nim Documentation (English)
+
+> A Clojure dialect that compiles to Nim → C → native binaries.
+
+## Table of Contents
+
+| # | Document | Description |
+|---|----------|-------------|
+| 01 | [Getting Started](01-getting-started.md) | Installation, build, CLI commands, quick examples |
+| 02 | [Architecture](02-architecture.md) | Compiler pipeline, design decisions, internal structure |
+| 03 | [AI Integration](03-ai-integration.md) | DeepSeek, OpenAI, MiMo — error assistance, code generation, optimization, debugging |
+| 04 | [API Reference](04-api-reference.md) | JSON REPL protocol, operations, tool-call format |
+| 05 | [User Guide](05-user-guide.md) | Macros, threading, interop, advanced patterns |
+| 06 | [Roadmap](06-roadmap.md) | Completed phases, future plans, performance targets |
+
+## Quick Start
+
+```bash
+git clone https://gitlab.com/balvatar/lisp-nim.git
+cd lisp-nim
+make build
+make check        # build + tests + examples
+./cljnim repl     # human REPL
+```
+
+## Stats
+
+- **Tests:** 276+ across 8 suites
+- **Compiler:** Nim → C → native
+- **Targets:** Linux, macOS, Windows, JS, WASM, C shared libraries
+- **AI Support:** DeepSeek API, OpenAI-compatible, Xiaomi MiMo