fix(python): add template-output-simple to conformance expected-failures

FR6-ts (commits 0a17422→ed3c14d) added the template-output-simple
fixture to fixtures/conformance/ without updating Python's expected-
failures. Python's loader doesn't yet register the template.* metatype
cluster (per the FR-003/FR-004 work pinned post-foundation), so the new
fixture surfaces as ERR_UNKNOWN_TYPE on Python conformance.

Cross-port hygiene fix: list it alongside the other template fixtures
Python doesn't yet support (template-output-and-prompt, template-prompt-
simple). Python expected-failures stays consistent; pass count returns
to 90/91 (the remaining failure — doc-common-attrs-on-all-types — is a
pre-existing gap from commit fc99cd6, separate from this work).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: dmealing

server/python/tests/conformance/conformance-expected-failures.json

@@ -7,6 +7,7 @@
     "error-template-required-slot-missing",
     "origin-collection-simple",
     "template-output-and-prompt",
+    "template-output-simple",
     "template-prompt-simple"
   ]
 }