Add post pinning feature for project feeds

[SylvainChevalier]

Summary

This PR adds the ability for project admins to pin posts to the top of their project's feed, similar to the existing comment pinning feature.

Key Changes

Backend:

• Added is_pinned boolean field to the Post model with database indexing
• Implemented pin_post() and unpin_post() service functions in posts/services/common.py
• Created post_toggle_pin_api_view() endpoint that requires admin permissions to pin/unpin posts
• Updated get_posts_feed() to apply pinned post ordering logic:
  • Pinned posts appear at the top of their default project's feed
  • Pinning only applies when the feed is scoped to a single project (tournament, community, or explicit default project)
  • Pinning is ignored for unscoped feeds (main feed) and search/similarity results
  • Uses Django Case/When annotation to prioritize pinned posts while maintaining secondary sort order
• Added can_pin_post() permission check to ObjectPermission class
• Added URL route for the toggle-pin endpoint

Frontend:

• Added pin/unpin toggle to the post dropdown menu (admin-only)
• Displays a thumbtack icon on pinned posts in the post card
• Implemented optimistic UI updates with error handling
• Added togglePinPost() server action and API method
• Added i18n messages for pin/unpin actions and notifications
• Updated Post type to include is_pinned field

Tests:

• Added three comprehensive test cases covering:
  • Pinned posts appearing above unpinned posts in project feeds
  • Pinning only affecting the default project feed (not repost feeds)
  • Pinning being ignored in unscoped feeds
• Added integration test for the toggle-pin API endpoint with permission checks

Implementation Details

• Pinning respects the post's default_project relationship, ensuring pins only apply to the project where the post was originally created
• The feature uses a Case/When annotation to add a priority field (is_pinned_first) that sorts pinned posts first, then applies the requested ordering
• Admin permission is enforced at the API level using the existing permission system

https://claude.ai/code/session_01T4pYzdkyDaxzUry6iQP684

[coderabbitai]

Important

Draft PR not reviewed

Draft PRs are not automatically reviewed by default.

• Trigger a manual review

To automatically review draft PRs, update your CodeRabbit configuration:

reviews:
  auto_review:
    drafts: true

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[SylvainChevalier]

Heads up on the one red check — it's infra, not the code.

All code-relevant checks are green: Backend Checks, Frontend Checks, integration-tests, Email Template Checks, CodeQL (python/actions/js), and Docker build all pass.

The only failure is Deploy Preview App, and it's unrelated to this diff. Fly's abuse filter rejects the auto-generated preview app name:

Creating new Fly app: metaculus-pr-5119-claude-github-issue-3223-kip30
Error: ... Name blocked by abuse filter. GitHub is a common phishing target,
please select a new app name that doesn't contain GitHub

The app name is derived from the branch name (claude/github-issue-3223-kip300), which contains the substring github. Any branch with github in its name will hit this. I'm keeping the assigned branch name, so I'm not fixing this from the code side — it would need either a branch rename or a tweak to the preview workflow's app-name derivation (e.g. strip/replace github when building APP_NAME). Flagging rather than acting on it since it's outside this change.

---

Generated by Claude Code

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will not be closed automatically, but please consider updating it or closing it if it is no longer relevant.

[github-actions]

🚀 Preview Environment

Your preview environment is ready!

Resource	Details
🌐 Preview URL	https://metaculus-pr-5119-issue-3223-kip300-preview.mtcl.cc
📦 Docker Image	ghcr.io/metaculus/metaculus:issue-3223-kip300-db0ef64
🗄️ PostgreSQL	NeonDB branch preview/pr-5119-issue-3223-kip300
⚡ Redis	Fly Redis mtc-redis-pr-5119-issue-3223-kip300

Details

• Commit: e243d895a8f36ad07a61f40628489dc7e10806cc
• Branch: claude/github-issue-3223-kip300
• Fly App: metaculus-pr-5119-issue-3223-kip300

---

ℹ️ Preview Environment Info

Isolation:

• PostgreSQL and Redis are fully isolated from production
• Each PR gets its own database branch and Redis instance
• Changes pushed to this PR will trigger a new deployment

Limitations:

• Background workers and cron jobs are not deployed in preview environments
• If you need to test background jobs, use Heroku staging environments

Cleanup:

• This preview will be automatically destroyed when the PR is closed