Support multiple `create-pull-request` and `push-to-pull-request-branch`

[dsyme]

In this run, the Repo Maintainer agentic workflow tried to create multiple pull requests in one run.

https://github.com/fsprojects/FSharp.Control.AsyncSeq/actions/runs/22240371333/job/64342379975

The safe output MCP collector was called multipe times and didn't fail this, and I think the aw.patch witll just get overridden and things will get all messed up.

We should support creating multiple pull requests in each run, labelling them aw-{branch-name-1}.patch, aw-{branch-name-2}.patch and so on. Change the name of aw.patch to aw-{branch-name-1}.patch even if there is only one of them.

THe code that consumes and applies pull requests will of course need updating - any other code mentioning aw.patch should get updated too .

Multiple mixes of create-pull-request and push-to-pull-request-branch should also be supported

[dsyme]

Sure enough,

• 3 create-pull-request were called
• only one PR got created - using the metadata from the first and the patch from the last!

https://github.com/fsprojects/FSharp.Control.AsyncSeq/pull/219/changes