feat: add 15 auto-test functions + destroy-test + versioning rules

Batch 1: ok, echo, error, cpu, slow
Batch 2: jsonout, recurse, bigdata, math, timestamp
Batch 3: multiline, encoding, nested, memory, chain
Tests: create, update (code_hash), idempotency, destroy, re-create
All 15 functions verified via curl with JWT auth

examples/auto-funcs/code/recurse/main.py

@@ -0,0 +1,8 @@
+def fib(n):
+    if n <= 1:
+        return n
+    return fib(n - 1) + fib(n - 2)
+
+def main():
+    result = fib(30)
+    return f"fib(30)={result}"