Add user autocomplete for test run assignee updates

[gondamol]

Summary

• replace the Test Run bulk assignee prompt() with a Bootstrap modal
• add a reusable typeahead.js user autocomplete backed by the existing User.filter JSON-RPC method
• keep manual assignee entry available when the user lacks auth.view_user
• keep the existing TestExecution.update flow and add view coverage for modal visibility/permission text

Fixes #2510

Verification

• cd tcms && .\node_modules\.bin\eslint.cmd static\js\jsonrpc.js testruns\static\testruns\js\get.js
• git diff --check

Test Coverage

• Added view assertions for the assignee modal and auth.view_user-dependent help text.

[Copilot]

Pull request overview

This PR improves the Test Run “bulk change assignee” UX by replacing the prompt() flow with a Bootstrap modal and adding a typeahead-backed user autocomplete powered by the existing User.filter JSON-RPC method. It also extends Django view coverage to assert that the assignee UI elements are only visible when the user has the necessary permissions.

Changes:

• Replace bulk assignee prompt() with a Bootstrap modal form in the Test Run “get” page.
• Add a typeahead.js user autocomplete that queries User.filter and maps the selected display value back to a username for TestExecution.update.
• Add view tests that check modal visibility based on testruns.change_testexecution permission.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
tcms/testruns/tests/test_views.py	Adds assertions ensuring the new assignee modal is present/absent depending on permissions.
tcms/testruns/templates/testruns/get.html	Introduces the Bootstrap modal markup for changing assignees in bulk.
tcms/testruns/static/testruns/js/get.js	Implements modal open/submit behavior and adds the User.filter-backed typeahead autocomplete.

Comments suppressed due to low confidence (1)

tcms/testruns/static/testruns/js/get.js:880

• The modal is closed by simulating a click on the close button. This is fragile (depends on the specific button selector) and bypasses Bootstrap’s modal API. Prefer closing with $('#change-assignee-modal').modal('hide') so the logic keeps working if the modal header markup changes.

        changeAssigneeBulk(selected.executionIds, assignee)
        $('#change-assignee-modal button.close').click()
        return false
    })

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[gondamol]

Updated the branch to address the review points:

• autocomplete now initializes only when the page reports perms.auth.view_user; users without that permission still get the modal and can enter an exact username/email/user ID manually
• moved the reusable user typeahead setup into tcms/static/js/jsonrpc.js
• replaced the close-button click with $('#change-assignee-modal').modal('hide')
• extended the view assertions for the user-view permission flag/help text

Rechecked:

• cd tcms && .\node_modules\.bin\eslint.cmd static\js\jsonrpc.js testruns\static\testruns\js\get.js
• git diff --check

[atodorov]

This seems to duplicate/build on top of
#4353 which in itself very much resembles #3250.

If you are willing to work on this we need to resolve comments on older contributions first, then build on top of that, not starting everything from scratch.

I will comment on the other PR shortly.