fix(ci): apps/ contract JSON edits run the Python lane

_PY_SKIP includes apps/, so a change to apps/shared/src/gateway-events.json
(or apps/desktop/src/lib/desktop-slash-registry.json) alone classified as
python:false and tests/tui_gateway/test_gateway_event_contract.py — the
only side that checks emitters against the JSON — never ran. "Either side
drifting turns both red" was true locally and false in CI for that
direction. A table of cross-language contract files now forces python:true
alongside frontend; two classifier rows pin it (they fail without the
allowlist).

scripts/ci/classify_changes.py

@@ -91,6 +91,16 @@ _PY_RELEVANT_SITE = (
     "website/docs/",
     "website/scripts/",
 )
+# Cross-language contract files: data committed under a frontend tree that a
+# pytest pins against the Python side (emitter inventory, command registry).
+# Editing only the JSON in an apps/-only PR would otherwise skip the one test
+# that can catch the drift, so these force the Python lane too.
+_PY_RELEVANT_CONTRACT_FILES = {
+    # tests/tui_gateway/test_gateway_event_contract.py
+    "apps/shared/src/gateway-events.json",
+    # tests/hermes_cli/test_desktop_slash_registry.py
+    "apps/desktop/src/lib/desktop-slash-registry.json",
+}
 
 # CI-sensitive files: eslint config, workflow files, composite actions.
 # Changes here can influence what code the autofix job executes and pushes to
@@ -147,7 +157,7 @@ def _is_nix(p: str) -> bool:
 
 
 def _py_irrelevant(p: str) -> bool:
-    if p.startswith(_PY_RELEVANT_SITE):
+    if p.startswith(_PY_RELEVANT_SITE) or p in _PY_RELEVANT_CONTRACT_FILES:
         return False
     return (
         _is_docs(p)

tests/ci/test_classify_changes.py

@@ -99,6 +99,16 @@ CASES = {
         _lanes(python=True, site=True),
     ),
     "frontend → no uv_lock": (["apps/desktop/src/store/profile.ts"], _lanes(frontend=True)),
+    # Cross-language contract JSON under apps/: the pytest that pins it against
+    # the Python side must run even when nothing else in the PR is Python.
+    "gateway-events contract JSON → python + frontend": (
+        ["apps/shared/src/gateway-events.json"],
+        _lanes(python=True, frontend=True),
+    ),
+    "desktop slash-registry JSON → python + frontend": (
+        ["apps/desktop/src/lib/desktop-slash-registry.json"],
+        _lanes(python=True, frontend=True),
+    ),
     # The published CIMD document is asserted about by the Python suite, so a
     # lone edit there must not skip the lane that would catch a bad edit.
     "cimd document → python + site": (