test(web): drop the host-skill context row from the conversation goldens

These goldens were recorded on a machine with personal skills under ~/.dsh and
~/.agents, so every one of them pinned a context-injection row a clean runner
cannot produce — which is why the browser lane failed on CI and passed
locally. master's scaffold fix confines skill-local's host-level roots to the
temp world; re-recording against it removes the row and nothing else.
seeded-history keeps its row: that scenario seeds the event itself.

apps/web/tests/snapshots/code-mode-round/ui.expected.md

@@ -11,10 +11,6 @@
   - img
 - button "编辑":
   - img
-- button "上下文注入":
-  - img
-  - img
-  - text: 上下文注入
 - 'button "Think The user wants me to write a single `run_code` program that:"':
   - img
   - img