[Improve] Hide PR analytics from the sidebar

[roomote-roomote]

Opened on behalf of Matt Rubens. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

Removed the PR analytics entry from the Analytics sidebar while retaining the existing PR analytics route for direct access.

Updated the focused navigation test to cover the hidden entry and preserved route behavior.

Why this change was made

The PR analytics surface should remain out of primary navigation until it is ready to be promoted again.

Impact

Users now see only Tasks and Costs in the Analytics sidebar. Existing direct links to PR analytics continue to work.

Screenshots

[roomote-roomote]

1 issue outstanding. See task

• apps/web/src/app/(authenticated)/analytics/AnalyticsShell.tsx:60-63: The direct ?object=pullRequests view now falls back to tasks as its active item. The desktop sidebar highlights Tasks and the mobile selector displays Tasks while the page title and content are PRs, which misrepresents the current page. Keep the hidden PR view unselected instead and cover that state in the navigation test.

_{Reviewed db8d4f2}