* Add missing `policy` attribute to `WebPushSubscriptionSerializer`

Fixes #23145

* Add tests

* Add option to make the landing page be /about even when trends are enabled

* Restablish /explore as landing page by default

Instead of cutting immediately, cut after one recursion.

* Add requested_by to relationship maps

* Display whether an account has requested to follow you on their profile

* Add maskable icon support for Android

* Update manifest_serializer.rb

* Fix linting issue

Fixes #20111

* Add `sensitized` to Admin::Account serializer (fix #19148)

* remove whitespace, please linter

* Change “Translate” button to only show up when a translation backend is configured

Fixes #19346

* Add `translation` attribute to /api/v2/instance to expose whether the translation feature is enabled

Fixes #19328

- Fix theme color
- Fix elephant being too big on error page on small screens
- Remove "Follows and Followers" link from navigation panel

* Change featured tag updates to add/remove activity

* Fix to check for the existence of feature tag

* Rename service and worker

* Merge AddHashtagSerializer with AddSerializer

* Undo removal of sidekiq_options

And update all descriptions

* Change public accounts pages to mount the web UI

* Fix handling of remote usernames in routes

- When logged in, serve web app
- When logged out, redirect to permalink
- Fix `app-body` class not being set sometimes due to name conflict

* Fix missing `multiColumn` prop

* Fix failing test

* Use `discoverable` attribute to control indexing directives

* Fix `<ColumnLoading />` not using `multiColumn`

* Add `noindex` to accounts in REST API

* Change noindex directive to not be rendered by default before a route is mounted

* Add loading indicator for detailed status in web UI

* Fix missing indicator appearing while account is loading in web UI

* Add LIMIT of featured tag to instance API response

* Add featured_tags_collection_url to Account

* Add synchronization of remote featured tags

* Deliver update activity when updating featured tag

* Remove featured_tags_collection_url

* Revert "Add featured_tags_collection_url to Account"

This reverts commit cff349fc27.

* Add hashtag sync from featured collections

* Fix tag name normalize

* Add target option to fetch featured collection

* Refactor fetch_featured_tags_collection_service

* Add LIMIT of featured tag to v1/instance API response

Remove separate server hero setting

Cherry-picked d2528b26b6

Conflicts:
- `app/serializers/initial_state_serializer.rb`:
  Upstream changed stuff, we had extra attributes.
  Applied upstream changes while keeping our extra attributes.
- `app/serializers/rest/instance_serializer.rb`:
  Upstream actually moved that to `app/serializers/rest/v1/instance_serializer.rb`,
  so updated that file by keeping our extra attributes, and took upstream's
  version of `app/serializers/rest/instance_serializer.rb`.
- `spec/views/about/show.html.haml_spec.rb`:
  Took upstream's version.

* Remove timeline preview link from nav panel when not signed-in

* Always enable server stats

Source string no longer localized, Markdown instead of raw HTML

* Move ActivityPub::FetchRemoteAccountService to ActivityPub::FetchRemoteActorService

ActivityPub::FetchRemoteAccountService is kept as a wrapper for when the actor is
specifically required to be an Account

* Refactor SignatureVerification to allow non-Account actors

* fixup! Move ActivityPub::FetchRemoteAccountService to ActivityPub::FetchRemoteActorService

* Refactor ActivityPub::FetchRemoteKeyService to potentially return non-Account actors

* Refactor inbound ActivityPub payload processing to accept non-Account actors

* Refactor inbound ActivityPub processing to accept activities relayed through non-Account

* Refactor how Account key URIs are built

* Refactor Request and drop unused key_id_format parameter

* Rename ActivityPub::Dereferencer `signature_account` to `signature_actor`