[feature] Implement Mastodon-compatible roles (#3136)

* Implement Mastodon-compatible roles

- `Account.role` should only be available through verify_credentials for checking current user's permissions
- `Account.role` now carries a Mastodon-compatible permissions bitmap and a marker for whether it should be shown to the public
- `Account.roles` added for *public* display roles (undocumented but stable since Mastodon 4.1)
- Web template now uses only public display roles (no user-visible change here, we already special-cased the `user` role)

* Handle verify_credentials case for default role

* Update JSON exact-match tests

* Address review comments

* Add blocks bit to admin permissions bitmap

internal/api/client/statuses/statushistory_test.go

@@ -118,10 +118,7 @@ func (suite *StatusHistoryTestSuite) TestGetHistory() {
       "last_status_at": "2024-01-10T09:24:00.000Z",
       "emojis": [],
       "fields": [],
-      "enable_rss": true,
-      "role": {
-        "name": "user"
-      }
+      "enable_rss": true
     },
     "poll": null,
     "media_attachments": [],