* Fix being able to import more than allowed number of follows

Without this commit, if someone tries importing a second list of accounts to
follow before the first one has been processed, this will queue imports for
the two whole lists, even if they exceed the account's allowed number of
outgoing follows.

This commit changes it so the individual queued imports aren't exempt from
the follow limit check (they remain exempt from the rate-limiting check
though).

* Catch validation errors to not re-queue failed follows

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

* Delete status records by batches of 50

* Do not precompute values that are only used once

* Do not generate redis events for removal of public toots older than two weeks

* Filter reported toots a priori for polls and status deletion

* Do not process reblogs when cleaning up public timelines

As in Mastodon proper, reblogs don't appear in public TLs

* Clean the deleted account's own feed in one go

* Refactor Account#clean_feed_manager and List#clean_feed_manager

* Delete instead of destroy a few more associations

* Fix preloading

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

* Fix external user creation failing when invite request text is required

Also fixes tootctl-based user creation.

* Add test about invites when invite request text is otherwise required

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

* Fix deleting polls not deleting notifications

* Fix fav notification deletion when deleting a toot

* Refactor DeleteAccountService spec

* Add DeleteAccountService tests for other associations and notifications

* Add favourite handling spec in status removal

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

* Fix ResolveAccountService accepting mismatching acct: URI

* Set attributes that should be updated regardless of suspension

* Fix key fetching

* Automatically merge remote accounts with duplicate `uri`

* Add tests

* Add "tootctl accounts fix-duplicates"

Finds duplicate accounts sharing a same ActivityPub `id`, re-fetch them and
merge them under the canonical `acct:` URI.

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

* Improve searching for private toots from URL

Most of the time, when sharing toots, people use the toot URL rather than
the toot URI, which makes sense since it is the user-facing URL.

In Mastodon's case, the URL and URI are different, and Mastodon does not
have an index on URL, which means searching a private toot by URL is done
with a slow query that will only succeed for very recent toots.

This change gets rid of the slow query, and attempts to guess the URI from
URL instead, as Mastodon's are predictable.

* Add tests

* Only return status with guessed uri if url matches

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

* Fix admin being able to suspend their own instance account

* Add text about the instance's own actor in admin view

* Change instance actor notice from flash message to template

* Do not list local instance actor in account moderation list

- Reduce duplicate queries
- Remove n+1 queries
- Add accounts count to detailed view
- Add separate action log entry for updating existing domain blocks

* Add honeypot fields to limit non-specialized spam

Add two honeypot fields: a fake website input and a fake password confirmation
one. The label/placeholder/aria-label tells not to fill them, and they are
hidden in CSS, so legitimate users should not fall into these.

This should cut down on some non-Mastodon-specific spambots.

* Require a 3 seconds delay before submitting the registration form

* Fix tests

* Move registration form time check to model validation

* Give people a chance to clear the honeypot fields

* Refactor honeypot translation strings

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

Fixes #15191

* Fix webfinger redirect handling in ResolveAccountService

ResolveAccountService#process_webfinger! handled a one-step webfinger
redirection, but only accepting the result if it matched the exact URI passed
as input, defeating the point of a redirection check.

Instead, use the same logic as in `ActivityPub::FetchRemoteAccountService`,
updating the resulting `acct:` URI with the result of the first webfinger
query.

* Add tests

* Add ability to export bookmarks

* Add support for importing bookmarks

* Add bookmark import tests

* Add bookmarks export test

If someone tries logging in to an account and is prompted for a 2FA
code or sign-in token, even if the account's password or e-mail is
updated in the meantime, the session will show the prompt and allow
the login process to complete with a valid 2FA code or sign-in token

* Add account sensitized

* Fix i18n normalize

* Fix description and spec

* Fix spec

* Fix wording

* Add support for followers synchronization on the receiving end

Check the `collectionSynchronization` attribute on `Create` and `Announce`
activities and synchronize followers from provided collection if possible.

* Add tests for followers synchronization on the receiving end

* Add support for follower synchronization on the sender's end

* Add tests for the sending end

* Switch from AS attributes to HTTP header

Replace the custom `collectionSynchronization` ActivityStreams attribute by
an HTTP header (`X-AS-Collection-Synchronization`) with the same syntax as
the `Signature` header and the following fields:
- `collectionId` to specify which collection to synchronize
- `digest` for the SHA256 hex-digest of the list of followers known on the
   receiving instance (where “receiving instance” is determined by accounts
   sharing the same host name for their ActivityPub actor `id`)
- `url` of a collection that should be fetched by the instance actor

Internally, move away from the webfinger-based `domain` attribute and use
account `uri` prefix to group accounts.

* Add environment variable to disable followers synchronization

Since the whole mechanism relies on some new preconditions that, in some
extremely rare cases, might not be met, add an environment variable
(DISABLE_FOLLOWERS_SYNCHRONIZATION) to disable the mechanism altogether and
avoid followers being incorrectly removed.

The current conditions are:
1. all managed accounts' actor `id` and inbox URL have the same URI scheme and
   netloc.
2. all accounts whose actor `id` or inbox URL share the same URI scheme and
   netloc as a managed account must be managed by the same Mastodon instance
   as well.

As far as Mastodon is concerned, breaking those preconditions require extensive
configuration changes in the reverse proxy and might also cause other issues.

Therefore, this environment variable provides a way out for people with highly
unusual configurations, and can be safely ignored for the overwhelming majority
of Mastodon administrators.

* Only set follower synchronization header on non-public statuses

This is to avoid unnecessary computations and allow Follow-related
activities to be handled by the usual codepath instead of going through
the synchronization mechanism (otherwise, any Follow/Undo/Accept activity
would trigger the synchronization mechanism even if processing the activity
itself would be enough to re-introduce synchronization)

* Change how ActivityPub::SynchronizeFollowersService handles follow requests

If the remote lists a local follower which we only know has sent a follow
request, consider the follow request as accepted instead of sending an Undo.

* Integrate review feeback

- rename X-AS-Collection-Synchronization to Collection-Synchronization
- various minor refactoring and code style changes

* Only select required fields when computing followers_hash

* Use actor URI rather than webfinger domain in synchronization endpoint

* Change hash computation to be a XOR of individual hashes

Makes it much easier to be memory-efficient, and avoid sorting discrepancy issues.

* Marginally improve followers_hash computation speed

* Further improve hash computation performances by using pluck_each

There are edge cases where requests to certain hosts timeout when
using the vanilla HTTP.rb gem, which the goldfinger gem uses. Now
that we no longer need to support OStatus servers, webfinger logic
is so simple that there is no point encapsulating it in a gem, so
we can just use our own Request class. With that, we benefit from
more robust timeout code and IPv4/IPv6 resolution.

Fix #14091

* Add bell button

Fix #4890

* Remove duplicate type from post-deployment migration

* Fix legacy class type mappings

* Improve query performance with better index

* Fix validation

* Remove redundant index from notifications

* Do not serve account actors at all in limited federation mode

When an account is fetched without a signature from an allowed instance,
return an error.

This isn't really an improvement in security, as the only information that was
previously returned was required protocol-level info, and the only personal bit
was the existence of the account. The existence of the account can still be
checked by issuing a webfinger query, as those are accepted without signatures.

However, this change makes it so that unallowed instances won't create account
records on their end when they find a reference to an unknown account.

The previous behavior of rendering a limited list of fields, instead of not
rendering the actor at all, was in order to prevent situations in which two
instances in Authorized Fetch mode or Limited Federation mode would fail to
reach each other because resolving an account would require a signed query…
from an account which can only be fetched with a signed query itself. However,
this should now be fine as fetching accounts is done by signing on behalf of
the special instance actor, which does not require any kind of valid signature
to be fetched.

* Fix tests

- Disallow suspended accounts from revoking sessions and apps
- Allow suspended accounts to access exports

* Check for and record reblog info atomically

Instead of using ZREVRANK to determine whether a reblog is a new reblog or not,
use ZADD's NX option to perform the check/addition option atomically.

* Replace ZREVRANK call with ZSCORE key which is more efficient

* Make tests a bit stricter

* Fix off-by-one

* Add database support for list show-reply preferences

* Add backend support to read and update list-specific show_replies settings

* Add basic UI to set list replies setting

* Add specs for list replies policy

* Switch "cycling" reply policy link to a set of radio inputs

* Capitalize replies_policy strings

* Change radio button design to be consistent with that of the directory explorer

This is a leftover for the work done in #14466.

* feat: add possibility of adding WebAuthn security keys to use as 2FA

This adds a basic UI for enabling WebAuthn 2FA. We did a little refactor
to the Settings page for editing the 2FA methods – now it will list the
methods that are available to the user (TOTP and WebAuthn) and from
there they'll be able to add or remove any of them.
Also, it's worth mentioning that for enabling WebAuthn it's required to
have TOTP enabled, so the first time that you go to the 2FA Settings
page, you'll be asked to set it up.
This work was inspired by the one donde by Github in their platform, and
despite it could be approached in different ways, we decided to go with
this one given that we feel that this gives a great UX.

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* feat: add request for WebAuthn as second factor at login if enabled

This commits adds the feature for using WebAuthn as a second factor for
login when enabled.
If users have WebAuthn enabled, now a page requesting for the use of a
WebAuthn credential for log in will appear, although a link redirecting
to the old page for logging in using a two-factor code will also be
present.

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* feat: add possibility of deleting WebAuthn Credentials

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* feat: disable WebAuthn when an Admin disables 2FA for a user

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* feat: remove ability to disable TOTP leaving only WebAuthn as 2FA

Following examples form other platforms like Github, we decided to make
Webauthn 2FA secondary to 2FA with TOTP, so that we removed the
possibility of removing TOTP authentication only, leaving users with
just WEbAuthn as 2FA. Instead, users will have to click on 'Disable 2FA'
in order to remove second factor auth.
The reason for WebAuthn being secondary to TOPT is that in that way,
users will still be able to log in using their code from their phone's
application if they don't have their security keys with them – or maybe
even lost them.

* We had to change a little the flow for setting up TOTP, given that now
  it's possible to setting up again if you already had TOTP, in order to
  let users modify their authenticator app – given that now it's not
  possible for them to disable TOTP and set it up again with another
  authenticator app.
  So, basically, now instead of storing the new `otp_secret` in the
  user, we store it in the session until the process of set up is
  finished.
  This was because, as it was before, when users clicked on 'Edit' in
  the new two-factor methods lists page, but then went back without
  finishing the flow, their `otp_secret` had been changed therefore
  invalidating their previous authenticator app, making them unable to
  log in again using TOTP.

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* refactor: fix eslint errors

The PR build was failing given that linting returning some errors.
This commit attempts to fix them.

* refactor: normalize i18n translations

The build was failing given that i18n translations files were not
normalized.
This commits fixes that.

* refactor: avoid having the webauthn gem locked to a specific version

* refactor: use symbols for routes without '/'

* refactor: avoid sending webauthn disabled email when 2FA is disabled

When an admins disable 2FA for users, we were sending two mails
to them, one notifying that 2FA was disabled and the other to notify
that WebAuthn was disabled.
As the second one is redundant since the first email includes it, we can
remove it and send just one email to users.

* refactor: avoid creating new env variable for webauthn_origin config

* refactor: improve flash error messages for webauthn pages

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* Add support for inlined objects in activity audience

* Add tests

* Fix not being able to unbookmark toots when blocked by their author

* Add tests

* Increase DNS timeout from 1 second to 5 seconds for MX check

1 seconds is rather short when using a recursive DNS resolver which
hasn't got a cached result already available. Use 5 seconds instead,
which is the timeout value we use for outgoing HTTP queries.

* Add more precise error messages for invalid e-mail addresses

* Change content-type to be always computed from file data

Restore previous behavior, detecting the content-type isn't very
expensive, and some instances may serve files as application/octet-stream
regardless of their true type, making fetching media from them fail, while
it used to work pre-3.2.0.

* Add test