feat(plugins): show plugin logs on detail page via Docs/Logs tablist

Add a Logs tab beside Documentation on the plugin detail page, showing
the output a plugin prints through the standard Python logger (per the
wiki style guide). Logs are captured from the plugin's stderr by the
plugin runtime and fetched on demand.

- Bump langbot-plugin pin to 0.4.4 (adds GET_PLUGIN_LOGS action)
- plugin_connector/handler: get_plugin_logs RPC client
- HTTP route GET /api/v1/plugins/<author>/<name>/logs (limit + level)
- Frontend: wrap detail right panel in Docs/Logs Tabs; PluginLogs
  component with level filter, manual + 3s auto refresh, bottom-follow
- i18n: 7 new keys across all 8 locales

src/langbot/pkg/api/http/controller/groups/plugins.py

@@ -271,6 +271,22 @@ class PluginsRouterGroup(group.RouterGroup):
             readme = await self.ap.plugin_connector.get_plugin_readme(author, plugin_name, language=language)
             return self.success(data={'readme': readme})
 
+        @self.route(
+            '/<author>/<plugin_name>/logs',
+            methods=['GET'],
+            auth_type=group.AuthType.USER_TOKEN_OR_API_KEY,
+        )
+        async def _(author: str, plugin_name: str) -> quart.Response:
+            try:
+                limit = int(quart.request.args.get('limit', 200))
+            except (TypeError, ValueError):
+                limit = 200
+            level = quart.request.args.get('level') or None
+            logs = await self.ap.plugin_connector.get_plugin_logs(
+                author, plugin_name, limit=limit, level=level
+            )
+            return self.success(data={'logs': logs})
+
         @self.route(
             '/<author>/<plugin_name>/icon',
             methods=['GET'],