fix(intern-decision-serve): 0.1.2 treats empty/null images as absent

Audit finding on 0.1.1: a Jev client that always sends an images array with no
images was rejected for nothing. Only a non-empty value is 422 now. Also aligns
the contract's response example with the wire (model is the name@revision
string, not an object).

Re-accepted live: images []/null -> 200, ["a.png"] -> 422; JevBench all 202/231,
hard 83/111, 0 changed rows across the bench's r1..r4 (924).

services/intern-decision-serve/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "intern-decision-serve"
-version = "0.1.1"
+version = "0.1.2"
 description = "Intern-Decision-4B (its own inference.py) behind semif-serve's HTTP surface"
 requires-python = ">=3.12"
 dependencies = [