[frontend] Show profile-incomplete dialog when adding a friend

[aapeliv]

Stacked on top of #8520. Apply the same client-side incomplete-profile gate to the friend-request action that already exists for messaging and host requests: clicking "Add friend" with an incomplete profile now opens `ProfileIncompleteDialog` instead of firing the request and showing the backend error.

Changes:

• Extend `ProfileIncompleteDialog`'s `attempted_action` union with `send_friend_request`.
• Add the matching `send_friend_request` label to `features/dashboard/locales/en.json`.
• Wire `useAccountInfo` into `AddFriendButton` and gate the mutation on `profileComplete`, mirroring `MessageUserButton`.

Testing

• `yarn test --testPathPattern AddFriendButton` — 5/5 passing, including a new "pops up incomplete profile note if profile is incomplete" case.
• `yarn lint:fix` and `yarn format` clean.
• Existing `MessageUserButton` / `ProfileIncompleteDialog` tests still pass.

Web frontend checklist

• There are no console warnings when running the app
• Added tests where relevant
• Clicked around my changes running locally and it works
• Checked Desktop, Mobile and Tablet screen sizes

For maintainers

• Maintainers can push commits to my branch
• Maintainers can merge this PR for me

This PR was created with the Couchers PR skill.

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Project	Deployment	Actions	Updated (UTC)
couchers	Ready	Preview	May 10, 2026 4:01am

The base branch was changed.

[github-actions]

📝 Release Notes

This PR should be included in the release notes.

Suggested release note:

Improved friend requests by showing a clear prompt to complete your profile before sending one

🤖 Bot Debug Information

Model: couchers.openai.gpt-5.4
Decision: include
Reasoning: This is a noticeable user-facing UX improvement: instead of failing with a backend error, users with incomplete profiles now get a clear dialog explaining they need to complete their profile before sending a friend request. It affects a core social action and improves the experience around an important platform rule.