MSC4115 has now completed FCP, so we can enable it by default and switch
to the stable identifier.

Based on [MSC3575](https://github.com/matrix-org/matrix-spec-proposals/pull/3575): Sliding Sync

Fix `newly_left` rooms not appearing if we returned early when `membership_snapshot_token.is_before_or_eq(to_token.room_key)`. 

Introduced in https://github.com/element-hq/synapse/pull/17187 (part of Sliding Sync)

The tests didn't catch it because they had a small typo in it `room_id1` vs `room_id2`.

Found while working on https://github.com/element-hq/synapse/pull/17293

Add `event.internal_metadata.instance_name` (the worker instance that persisted the event) to go alongside the existing `event.internal_metadata.stream_ordering`.

`instance_name` is useful to properly compare and query for events with a token since you need to compare both the `stream_ordering` and `instance_name` against the vector clock/`instance_map` in the `RoomStreamToken`.

This is pre-requisite work and may be used in https://github.com/element-hq/synapse/pull/17293

Adding `event.internal_metadata.instance_name` was first mentioned in the initial Sliding Sync PR while pairing with @erikjohnston, see https://github.com/element-hq/synapse/pull/17187/commits/09609cb0dbca3a4cfd9fbf90cc962e765ec469c0#diff-5cd773fb307aa754bd3948871ba118b1ef0303f4d72d42a2d21e38242bf4e096R405-R410

PR where this was introduced: https://github.com/matrix-org/synapse/pull/14817

### What does this affect?

`get_last_event_in_room_before_stream_ordering(...)` is used in Sync v2 in a lot of different state calculations.

`get_last_event_in_room_before_stream_ordering(...)`  is also used in `/rooms/{roomId}/members` 

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

This clarifies in the comments that the MSC is being used in matrix.org

See #17270

https://github.com/matrix-org/matrix-spec-proposals/pull/4151

This is intended to be enabled by default for immediate use. When FCP is
complete, the unstable endpoint will be dropped and stable endpoint
supported instead - no backwards compatibility is expected for the
unstable endpoint.

Spawning from https://github.com/element-hq/synapse/pull/17187#discussion_r1619492779 around wanting to put `SlidingSyncBody` (parse the request in the rest layer), `SlidingSyncConfig` (from the rest layer, pass to the handler), `SlidingSyncResponse` (pass the response from the handler back to the rest layer to respond) somewhere that doesn't contaminate the imports and cause circular import issues.

 - Moved Pydantic parsing models to `synapse/types/rest`
 - Moved handler types to `synapse/types/handlers`

If the stream ID in the unconverted table is ahead of the device lists
ID gen, then it can break all /sync requests that had an ID from ahead
of the table.

The fix is to make sure we add the unconverted table to the list of
tables we check at start up.

Broke in https://github.com/element-hq/synapse/pull/17229

Broke in https://github.com/element-hq/synapse/pull/17215

Wrong retention policy being used when filtering events (lint `ControlVarUsedAfterBlockViolation` `WPS441`) (#17272)

Fix loop var being used outside block.

Before this change, we were always using the last room_id's retention policy for all events being filtered.

I found this bug with the [new lint rule, `ControlVarUsedAfterBlockViolation` `WPS441`](https://github.com/astral-sh/ruff/pull/11769), that I re-implemented in `ruff`. Shout-out to @reivilibre for all the help in the beginning! 

### Pull Request Checklist

<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->

* [x] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
  - Use markdown where necessary, mostly for `code blocks`.
  - End with either a period (.) or an exclamation mark (!).
  - Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [x] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct
(run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))

Add debug logging for when room keys are uploaded, including whether they are replacing other room keys. (#17266)

Fixes: #17013

Add logging for whether room keys are replaced
This is motivated by the Crypto team who need to diagnose crypto issues.

The existing opentracing logging is not enough because it is not enabled
for all users.

Based on [MSC3575](https://github.com/matrix-org/matrix-spec-proposals/pull/3575): Sliding Sync

This iteration only focuses on returning the list of room IDs in the sliding window API (without sorting/filtering).

Rooms appear in the Sliding sync response based on:

 - `invite`, `join`, `knock`, `ban` membership events
 - Kicks (`leave` membership events where `sender` is different from the `user_id`/`state_key`)
 - `newly_left` (rooms that were left during the given token range, > `from_token` and <= `to_token`)
 - In order for bans/kicks to not show up, you need to `/forget` those rooms. This doesn't modify the event itself though and only adds the `forgotten` flag to `room_memberships` in Synapse. There isn't a way to tell when a room was forgotten at the moment so we can't factor it into the from/to range.

### Example request

`POST http://localhost:8008/_matrix/client/unstable/org.matrix.msc3575/sync`

```json
{
  "lists": {
    "foo-list": {
      "ranges": [ [0, 99] ],
      "sort": [ "by_notification_level", "by_recency", "by_name" ],
      "required_state": [
        ["m.room.join_rules", ""],
        ["m.room.history_visibility", ""],
        ["m.space.child", "*"]
      ],
      "timeline_limit": 100
    }
  }
}
```

Response:
```json
{
  "next_pos": "s58_224_0_13_10_1_1_16_0_1",
  "lists": {
    "foo-list": {
      "count": 1,
      "ops": [
        {
          "op": "SYNC",
          "range": [0, 99],
          "room_ids": [
            "!MmgikIyFzsuvtnbvVG:my.synapse.linux.server"
          ]
        }
      ]
    }
  },
  "rooms": {},
  "extensions": {}
}
```

And fallback keys uploads. Only device keys need handling on master

It's just a waste of time if we won't even query the remote host as its
marked as down.

Broke in https://github.com/element-hq/synapse/pull/17215

c.f. #16675

Use fully-qualified `PersistedEventPosition` (`instance_name` and `stream_ordering`) when returning `RoomsForUser` to facilitate proper comparisons and `RoomStreamToken` generation.

Spawning from https://github.com/element-hq/synapse/pull/17187 where we want to utilize this change

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

This can happen on restarts of the service, due to old rooms being
pruned.

This was broken by the sentry 2.0 upgrade

Broke in v1.108.0