Conflicted shards

## Description

We have in the CouchDB logs some messages saying:

```
4 conflicted shards in cluster
```

We are using many small databases created with a single shard (`q=1`). We don't know which shards are in this state, nor what we can do about that.

## Steps to Reproduce

We don't know how to reproduce.

## Expected Behaviour

Well, if CouchDB could avoid to create conflicted shards, it would be nice. At least, some documentation for what to do in that case is expected.

## Your Environment

```json
{
"couchdb": "Welcome",
"version": "3.2.2",
"git_sha": "d5b746b7c",
"uuid": "b3ac19e755fb8720ec0be49b61088909",
"features": [
"access-ready",
"partitioned",
"pluggable-storage-engines",
"reshard",
"scheduler"
],
"vendor": {
"name": "The Apache Software Foundation"
}
}
```

```
# cat /etc/debian_version
11.7
# cat /etc/apt/sources.list.d/couchdb.list
deb https://apache.jfrog.io/artifactory/couchdb-deb/ bullseye main
```

## Additional Context

The issue names no source files or tests; start by locating the code that emits the “conflicted shards in cluster” log message and reviewing the shard-conflict handling around it. Use the reported q=1 setup and CouchDB 3.2.2 details as context. Done means identifying affected shards and documenting or correcting the supported response, with a reproducible test if the behavior is a bug.

Written by the indexing model from the issue text.