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/bigdata/main.py

@@ -0,0 +1,5 @@
+def main():
+    lines = []
+    for i in range(500):
+        lines.append(f"line-{i}: {'x' * 80}")
+    return "\n".join(lines)