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/memory/main.py

@@ -0,0 +1,6 @@
+import sys
+
+def main():
+    big_list = list(range(500000))
+    size_mb = sys.getsizeof(big_list) / (1024 * 1024)
+    return f"memory-alloc:{size_mb:.2f}MB len={len(big_list)}"