refactor: replace PR assignee workflow with Slack channel notification

[tomassrnka]

Summary

• Deletes the auto-request-same-site workflow that added assignees to PRs
• Replaces with pr-slack-notify that posts new PRs to #code-review-requests on Slack, tagging @pr-infra
• No automatic GitHub reviewer or assignee assignment — someone claims from Slack and self-assigns as reviewer
• CODEOWNERS unchanged (branch protection approval gating only)

Setup required (before merging)

• Create Slack channel #code-review-requests (or get its ID if it exists)
• Create Slack user group @pr-infra (or get its ID if it exists)
• Set repo variable SLACK_CHANNEL_ID — the channel ID
• Set repo variable SLACK_REVIEW_GROUP — the Slack user group ID for @pr-infra
• SLACK_BOT_TOKEN secret already exists

Test plan

• Set up the repo variables with test values
• Use workflow_dispatch to manually trigger with a test PR
• Verify message appears in #code-review-requests with @pr-infra tag
• Open a real PR and verify it posts automatically
• Verify no assignees or reviewers are auto-added

🤖 Generated with Claude Code

[cursor]

PR Summary

Medium Risk
Changes PR automation from GitHub-side assignee selection to Slack-based notifications and still runs on pull_request_target, so misconfiguration of Slack variables/secrets could break review routing or leak notifications.

Overview
This PR removes the automation that auto-selected same-site reviewers/assignees (including CODEOWNERS fallback and Slack DMs) and replaces it with a reusable workflow that posts newly opened/ready PRs to a configured Slack channel, tagging a configured review group so reviewers self-assign rather than being assigned automatically.

^{Reviewed by Cursor Bugbot for commit 0383df4. Bugbot is set up for automated code reviews on this repo. Configure here.}

[tomassrnka]

bugbot run

[cursor]

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit 6ac8860. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

Bugbot Autofix prepared fixes for both issues found in the latest run.

• ✅ Fixed: Missing workflow_dispatch trigger prevents manual testing
  • Added workflow_dispatch trigger with pr_number input to enable manual testing as described in the test plan.
• ✅ Fixed: Draft PRs trigger premature Slack notifications
  • Added condition if: github.event.pull_request.draft == false to skip notifications for draft PRs.

Or push these changes by commenting:

@cursor push 59839a64c2

Preview (59839a64c2)

diff --git a/.github/workflows/pr-slack-notify.yml b/.github/workflows/pr-slack-notify.yml
--- a/.github/workflows/pr-slack-notify.yml
+++ b/.github/workflows/pr-slack-notify.yml
@@ -5,15 +5,23 @@
     types:
       - opened
       - ready_for_review
+  workflow_dispatch:
+    inputs:
+      pr_number:
+        description: 'PR number to test with'
+        required: true
+        type: number
 
 permissions:
   contents: read
 
 jobs:
   notify:
+    if: github.event.pull_request.draft == false
     uses: e2b-dev/.github/.github/workflows/pr-slack-notify.yml@main
     secrets:
       SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}
     with:
       channel_id: ${{ vars.SLACK_CHANNEL_ID }}
       review_group: ${{ vars.SLACK_REVIEW_GROUP }}
+      pr_number: ${{ inputs.pr_number }}

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^{Reviewed by Cursor Bugbot for commit 2cdb2cb. Configure here.}

[cursor]

Draft PRs trigger premature Slack notifications

Low Severity

The opened event fires for all PRs including drafts. A draft PR will post to #code-review-requests tagging @pr-infra immediately on creation, and then again when marked ready for review via ready_for_review. This results in either a noisy premature notification for drafts, or a duplicate notification for PRs that transition from draft to ready.

 

^{Reviewed by Cursor Bugbot for commit 2cdb2cb. Configure here.}