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/chain/main.py

@@ -0,0 +1,9 @@
+import hashlib
+import json
+
+def main():
+    data = {"step": 1, "value": "start"}
+    for i in range(2, 6):
+        h = hashlib.sha256(json.dumps(data).encode()).hexdigest()[:8]
+        data = {"step": i, "prev_hash": h, "value": f"chain-{i}"}
+    return json.dumps(data)