feat: add fullscreen TUI and project updates

- New TUI screens: Main Menu, Compile, Run, REPL, AI Generator, AI Settings, Help
- AI configuration persisted in ~/.config/cljnim/config.json
- Added illwill dependency for terminal UI
- Updated experiments, examples, docs, and core modules

tests/test_eval.nim

@@ -1,4 +1,4 @@
-import unittest
+import unittest, strutils
 import ../src/types
 import ../src/eval
 
@@ -580,3 +580,28 @@ suite "Eval - Channels":
     discard eval("(def ch (chan))", env)
     let r = eval("(close! ch)", env)
     check r.ok
+
+suite "Eval - AI Functions (test doesn't require API keys)":
+  setup:
+    let env = newTopLevelEnv()
+
+  test "ai/generate returns string or error":
+    let r = eval("(ai/generate \"reverse a list\")", env)
+    if r.ok:
+      check r.value.kind == ckString
+    else:
+      check("API key" in r.error or "AI request failed" in r.error or "SSL" in r.error)
+
+  test "ai/optimize returns string or error":
+    let r = eval("(ai/optimize \"(reduce + nums)\")", env)
+    if r.ok:
+      check r.value.kind == ckString
+    else:
+      check("API key" in r.error or "AI request failed" in r.error or "SSL" in r.error)
+
+  test "ai/debug returns string or error":
+    let r = eval("(ai/debug (+ 1 2))", env)
+    if r.ok:
+      check r.value.kind == ckString
+    else:
+      check("API key" in r.error or "AI request failed" in r.error or "SSL" in r.error)