test(docker): a plugin template can take its own name; the overview's assertions follow its new tables (#5299, #5302)

render_plugin_template's first three arguments are positional-only, so the
service page's own `name` reaches the template. The overview names a service
rather than its replica containers, and a stack chip keeps the search it was
clicked under.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/_templates.py

@@ -16,7 +16,7 @@ def template_files() -> list[pathlib.Path]:
     return sorted(p for root in roots for p in root.rglob("*.html"))
 
 
-async def render_plugin_template(app, plugin: str, name: str, **ctx) -> str:
+async def render_plugin_template(app, plugin: str, name: str, /, **ctx) -> str:
     """Render plugins/<plugin>/templates/<name> with quart.render_template,
     whether or not the plugin is enabled in this app: the plugin's template
     folder goes ahead of the app's loader for the one render. Call inside