Add 'Copy ID to clipboard' action to work package context menus

[wielinde]

Adds a new context menu action that copies the work package's display_id
(e.g. "PROJ-42" in semantic mode or "42" in classic mode) to the clipboard.

The action appears:

• In the work package table right-click context menu, below 'Copy link to clipboard'
• In the work package split view and full view 'more' (three-dot) menu

Closes https://community.openproject.org/wp/STC-858

[github-actions]

Thank you for your submission, we really appreciate it. Like many open-source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution. You can sign the CLA by just posting a Pull Request Comment same as the below format.

---

I have read the CLA Document and I hereby sign the CLA

---

_{You can retrigger this bot by commenting recheck in this Pull Request. Posted by the CLA Assistant Lite bot.}

[github-actions]

Deploying openproject with ⚡ PullPreview

Field	Value
Latest commit	f92a507
Job	deploy
Status	✅ Deploy successful
Preview URL	https://pr-23822-work-package-co-ip-178-105-242-251.my.opf.run:443

View logs

[github-actions]

Warning

Flaky specs

• rspec ./modules/wikis/spec/features/admin/internal_provider_spec.rb[1:1]

🤖 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 #23822, linked for reference only):

- `rspec ./modules/wikis/spec/features/admin/internal_provider_spec.rb[1:1]`

Treat this as a standalone task, unrelated to PR #23822. Create a new branch from origin/dev and open a new pull request targeting dev — do not stack it on PR #23822 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 @wielinde 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 @wielinde, and request a review from @wielinde.
On every commit, set @wielinde 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.