feat: AI-assisted compilation and code generation

- New src/ai_assist.nim module with DeepSeek/OpenAI/MiMo API support
- AI explains compiler errors automatically when compilation fails
- New CLI command: cljnim ai '<description>' for code generation
- REPL :ai command for interactive AI assistance
- API keys read from environment vars (DEEPSEEK_API_KEY, OPENAI_API_KEY, MIMO_API_KEY)
- Tests for prompt building and response formatting
- Updated README with AI integration docs

README.md

@@ -103,6 +103,58 @@ $ ./cljnim repl --json
 
 See [`docs/AI_FIRST.md`](docs/AI_FIRST.md) for the full AI integration design.
 
+## AI-Powered Assistance
+
+Clojure/Nim can use paid AI APIs (DeepSeek, OpenAI, Xiaomi MiMo) to help you write and debug code.
+
+### Setup
+
+Set one of these environment variables:
+
+```bash
+# DeepSeek (recommended, fast & cheap)
+export DEEPSEEK_API_KEY="sk-..."
+
+# OpenAI / OpenRouter
+export OPENAI_API_KEY="sk-..."
+
+# Xiaomi MiMo
+export MIMO_API_KEY="..."
+```
+
+### Features
+
+**Auto-error explanation** — When compilation fails, the compiler automatically asks AI for a fix:
+```bash
+$ ./cljnim run broken.clj
+Compilation failed
+Error: type mismatch: got <int> but expected <string>
+💡 AI Suggestion:
+   The function `greet` expects a string but you passed an integer.
+   Fix: (defn greet [name] (str "Hello " name))
+```
+
+**REPL AI command** — Generate code interactively:
+```bash
+$ ./cljnim repl
+user> :ai function that calculates fibonacci using loop/recur
+🤖 Thinking...
+💡 AI Suggestion:
+   (defn fib [n]
+     (loop [a 0 b 1 i n]
+       (if (= i 0)
+         a
+         (recur b (+ a b) (dec i)))))
+```
+
+**CLI code generation** — Generate code from terminal:
+```bash
+$ ./cljnim ai "function that reads a file line by line"
+(defn read-lines [filename]
+  (let [content (slurp filename)]
+    (clojure.string/split-lines content)))
+```
+
 ## Architecture
 
 ```
@@ -131,14 +183,25 @@ See [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) for details.
 │   ├── reader.nim       # Clojure reader / EDN parser
 │   ├── emitter.nim      # Nim code generator
 │   ├── repl.nim         # Human & AI REPL
+│   ├── eval.nim         # Tree-walking interpreter
+│   ├── deps.nim         # Dependency resolution
+│   ├── core.nim         # Core runtime functions
 │   ├── types.nim        # Clojure value types
 │   ├── macros.nim       # Macro expansion engine
 │   └── runtime.nim      # Runtime implementation
 ├── lib/
-│   └── cljnim_runtime.nim   # Clojure runtime in Nim
+│   ├── cljnim_runtime.nim   # Clojure runtime in Nim
+│   ├── cljnim_pvec.nim      # Persistent Vector (HAMT)
+│   ├── cljnim_pmap.nim      # Persistent Map (HAMT)
+│   └── cljnim_async.nim     # core.async channels
 ├── examples/
 │   ├── hello.clj
-│   └── math.clj
+│   ├── math.clj
+│   ├── core.clj
+│   ├── macros.clj
+│   ├── ffi.clj
+│   ├── interop.clj
+│   └── ai_tools.clj
 ├── docs/                    # Documentation (EN + BG)
 ├── tests/
 ├── Makefile
@@ -148,19 +211,18 @@ See [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) for details.
 ## Supported Features
 
 ### Working Now ✅
-- Reader: numbers, strings, symbols, keywords, lists `()`, vectors `[]`
+- Reader: numbers, strings, symbols, keywords, lists `()`, vectors `[]`, maps `{}`
 - Special forms: `def`, `defn`, `fn`, `let`, `if`, `do`, `quote`
 - Arithmetic: `+`, `-`, `*`, `/`, `=`, `<`, `>`
-- Functions: `println`
+- Functions: `println`, `map`, `filter`, `reduce`
 - Human REPL and JSON REPL
 - AOT compilation to native binaries
-
-### In Progress 🔄
-- Persistent data structures (Vector, Map, Set)
-- `defmacro` system
+- Persistent data structures (Vector, Map, Set) via HAMT
+- Macro system (`defmacro`, `->`, `->>`, `and`, `or`, `when`, `cond`)
 - Nim/C interop
-- File operations from REPL
-- Git operations from REPL
+- File and Git operations from REPL
+- Tree-walking interpreter for fast REPL eval
+- Atoms, Agents, and core.async channels
 
 See [`docs/ROADMAP.md`](docs/ROADMAP.md) for the full roadmap.