[XWI-133] add queries to fetch page hierachy information

[Kharonus]

Ticket

XWI-133

What approach did you choose and why?

• add two internal queries
• add contracts, input and result model
• HINT: this PR is a first step of https://community.openproject.org/wp/XWI-107
• next step is amending the search service

[github-actions]

Caution

The provided work package version does not match the core version

Details:

• Work package URL: https://community.openproject.org/wp/XWI-133
• Work package version: not set
• Core version: 17.7.0

Please make sure that:

• The work package version OR your pull request target branch is correct

[Kharonus]

I hate it. And here I give the 🎤 to @NobodysNightmare and he can tell me: "Told you so."

What is happening? I voted to use a namespace called "internal" for queries and commands, that are not exposed via the registry. But I completely overlooked, that we already have an internal namespace for the provider type.

So, I'm ready to revisit that decision. WDYT? Shall I move all (2) queries out of this namespace and basically we rely that not exposing those query via the registry is the only indicator, that those are considered for "internal" use only?

[Kharonus]

Missing tests ...

[github-actions]

Warning

Flaky specs

• rspec ./spec/features/projects/lists/filters_spec.rb[1:6:1]

🤖 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 #24048, linked for reference only):

- `rspec ./spec/features/projects/lists/filters_spec.rb[1:6:1]`

Treat this as a standalone task, unrelated to PR #24048. Create a new branch from origin/dev and open a new pull request targeting dev — do not stack it on PR #24048 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 @Kharonus 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 @Kharonus, and request a review from @Kharonus.
On every commit, set @Kharonus 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.