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

src/ai_assist.nim

@@ -0,0 +1,160 @@
+# AI Assistance for Clojure/Nim Compiler
+# Supports DeepSeek API and OpenAI-compatible APIs (Xiaomi MiMo, etc.)
+# API keys are read from environment variables — never hardcoded.
+
+import std/[httpclient, json, os, strutils, uri]
+
+type
+  AiProvider* = enum
+    aiDeepSeek
+    aiOpenAiCompatible
+
+  AiConfig* = object
+    provider*: AiProvider
+    apiKey*: string
+    baseUrl*: string
+    model*: string
+    timeoutMs*: int
+
+  AiResponse* = object
+    ok*: bool
+    suggestion*: string
+    rawJson*: string
+
+proc detectConfig*(): AiConfig =
+  ## Auto-detect AI configuration from environment variables
+  result.timeoutMs = 15000
+
+  # DeepSeek
+  let deepseekKey = getEnv("DEEPSEEK_API_KEY", "")
+  if deepseekKey.len > 0:
+    return AiConfig(
+      provider: aiDeepSeek,
+      apiKey: deepseekKey,
+      baseUrl: "https://api.deepseek.com",
+      model: getEnv("DEEPSEEK_MODEL", "deepseek-chat"),
+      timeoutMs: parseInt(getEnv("AI_TIMEOUT_MS", "15000"))
+    )
+
+  # OpenAI-compatible (Xiaomi MiMo, OpenRouter, etc.)
+  let openaiKey = getEnv("OPENAI_API_KEY", "")
+  if openaiKey.len > 0:
+    return AiConfig(
+      provider: aiOpenAiCompatible,
+      apiKey: openaiKey,
+      baseUrl: getEnv("OPENAI_BASE_URL", "https://api.openai.com"),
+      model: getEnv("OPENAI_MODEL", "gpt-4o-mini"),
+      timeoutMs: parseInt(getEnv("AI_TIMEOUT_MS", "15000"))
+    )
+
+  # Xiaomi MiMo (OpenAI-compatible)
+  let mimoKey = getEnv("MIMO_API_KEY", "")
+  if mimoKey.len > 0:
+    return AiConfig(
+      provider: aiOpenAiCompatible,
+      apiKey: mimoKey,
+      baseUrl: getEnv("MIMO_BASE_URL", "https://api.mi-mo.ai"),
+      model: getEnv("MIMO_MODEL", "mimo-chat"),
+      timeoutMs: parseInt(getEnv("AI_TIMEOUT_MS", "15000"))
+    )
+
+  # No API key found
+  return AiConfig(provider: aiDeepSeek, apiKey: "", baseUrl: "", model: "", timeoutMs: 0)
+
+proc hasAiConfig*(): bool =
+  detectConfig().apiKey.len > 0
+
+proc buildErrorPrompt*(errorMsg, sourceCode, fileName: string): string =
+  ## Build a prompt for the AI to analyze a compiler error
+  result = """You are an expert Clojure/Nim compiler assistant. The user got a compilation error.
+
+**File:** """ & fileName & """
+
+**Source code:**
+```clojure
+""" & sourceCode & """
+```
+
+**Compiler error:**
+```
+""" & errorMsg & """
+```
+
+Please explain the error in simple terms and suggest a fix. Keep your response under 200 words.
+If the error is in Clojure code, show the corrected Clojure snippet.
+Respond in the same language as the user's source code comments (Bulgarian or English).
+"""
+
+proc buildGenerationPrompt*(description: string): string =
+  ## Build a prompt for AI code generation
+  result = """You are an expert Clojure programmer. Generate a Clojure function based on this description:
+
+""" & description & """
+
+Requirements:
+- Use idiomatic Clojure
+- Include docstring
+- Use loop/recur instead of recursion if possible
+- Return ONLY the Clojure code, no explanations
+"""
+
+proc callAiApi*(config: AiConfig, prompt: string): AiResponse =
+  ## Call the AI API and return the response
+  if config.apiKey.len == 0:
+    return AiResponse(ok: false, suggestion: "No AI API key configured. Set DEEPSEEK_API_KEY, OPENAI_API_KEY, or MIMO_API_KEY environment variable.")
+
+  let client = newHttpClient(timeout = config.timeoutMs)
+  defer: client.close()
+
+  let url = config.baseUrl & "/v1/chat/completions"
+  let body = %*{
+    "model": config.model,
+    "messages": [
+      {"role": "user", "content": prompt}
+    ],
+    "temperature": 0.3,
+    "max_tokens": 800
+  }
+
+  client.headers["Authorization"] = "Bearer " & config.apiKey
+  client.headers["Content-Type"] = "application/json"
+
+  try:
+    let resp = client.post(url, body = $body)
+    let respBody = resp.body
+    result.rawJson = respBody
+
+    if resp.code.int != 200:
+      return AiResponse(ok: false, suggestion: "AI API error (HTTP " & $resp.code.int & "): " & respBody)
+
+    let jsonResp = parseJson(respBody)
+    if jsonResp.hasKey("choices") and jsonResp["choices"].len > 0:
+      let content = jsonResp["choices"][0]["message"]["content"].getStr("")
+      return AiResponse(ok: true, suggestion: content, rawJson: respBody)
+    else:
+      return AiResponse(ok: false, suggestion: "Unexpected AI API response format", rawJson: respBody)
+
+  except CatchableError as e:
+    return AiResponse(ok: false, suggestion: "AI request failed: " & e.msg)
+
+proc explainError*(errorMsg, sourceCode, fileName: string): AiResponse =
+  ## High-level helper: explain a compiler error using AI
+  let config = detectConfig()
+  let prompt = buildErrorPrompt(errorMsg, sourceCode, fileName)
+  return callAiApi(config, prompt)
+
+proc generateCode*(description: string): AiResponse =
+  ## High-level helper: generate Clojure code from description
+  let config = detectConfig()
+  let prompt = buildGenerationPrompt(description)
+  return callAiApi(config, prompt)
+
+proc formatSuggestion*(response: AiResponse): string =
+  ## Format AI response for terminal display
+  if not response.ok:
+    return "💡 AI: " & response.suggestion
+
+  var res = "💡 AI Suggestion:\n"
+  for line in response.suggestion.splitLines():
+    res.add("   " & line & "\n")
+  return res