[OP-19880] Show correct counter for matching users on generic allocations

[klaustopher]

Ticket

https://community.openproject.org/projects/OP/work_packages/OP-19880

What are you trying to accomplish?

• Add a member filter for the user query
• Use that query instead of attaching in_project manually
• Show the correct counter how many users a generic allocation applies to
  • Remove the + prefix as this was not really a plus counter (like in the work package list)
  • Scope the count to only show project members. Right now it shows a global count

Screenshots

What approach did you choose and why?

Merge checklist

• Added/updated tests
• Added/updated documentation in Lookbook (patterns, previews, etc)
• Tested major browsers (Chrome, Firefox, Edge, ...)

[dfriquet]

The new query filter for users is a nice "side-effect" of this bugfix 👍 One performance and one UX question remain.

[github-actions]

Warning

Flaky specs

• rspec ./modules/backlogs/spec/features/inbox_column_spec.rb[1:7:1]

🤖 Ask Copilot to investigate

Copy the prompt below into a new comment on this PR to delegate the investigation to GitHub Copilot. It will look into the flakiness and open a separate pull request with you as reviewer.

@copilot The following spec(s) are flaky in CI (first seen on PR #24677, linked for reference only):

- `rspec ./modules/backlogs/spec/features/inbox_column_spec.rb[1:7:1]`

Treat this as a standalone task, unrelated to PR #24677. Create a new branch from origin/dev and open a new pull request targeting dev — do not stack it on PR #24677 or reuse that branch.

Follow the playbook in docs/development/testing/handling-flaky-tests/README.md to find the root cause and fix the underlying race — do not skip, delete, or weaken the spec to make it pass; disabling is a last resort per the playbook, and only with a bug ticket. Verify the fix by running the spec(s) repeatedly (e.g. `script/bulk_run_rspec --run-count 10`).

If you cannot reproduce the flake or are not confident in a fix after reasonable investigation, do not fabricate a change or skip the spec to force CI green. Instead, leave the pull request in draft and document what you tried, the suspected cause, and any leads in its description, then assign @klaustopher to take over.

Once the fix is verified, title the PR after the spec(s) it fixes, and use the PR description to explain the root cause, how the change resolves it, and the before/after results. Label the PR `flaky-spec`, assign @klaustopher, and request a review from @klaustopher.
On every commit, set @klaustopher as the sole co-author with a `Co-authored-by:` trailer (use their GitHub no-reply email so it links to their account), so it is traceable who dispatched the fix.