feat: remove legacy project columns, old settings tables, and app_id defaults

[Flo4604]

What does this PR do?

Fixes # (issue)

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Type of change

• Bug fix (non-breaking change which fixes an issue)
• Chore (refactoring code, technical debt, workflow improvements)
• Enhancement (small improvements)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How should this be tested?

• Test A
• Test B

Checklist

Required

• Filled out the "How to test" section in this PR
• Read Contributing Guide
• Self-reviewed my own code
• Commented on my code in hard-to-understand areas
• Ran pnpm build
• Ran pnpm fmt
• Ran make fmt on /go directory
• Checked for warnings, there are none
• Removed all console.logs
• Merged the latest changes from main onto my branch with git pull origin main
• My changes don't cause any responsiveness issues

Appreciated

• If a UI change was made: Added a screen recording or screenshots to this PR
• Updated the Unkey Docs if changes were necessary

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Project	Deployment	Actions	Updated (UTC)
dashboard	Ready	Preview, Comment	Feb 20, 2026 0:22am
engineering	Ready	Preview, Comment	Feb 20, 2026 0:22am

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[Flo4604]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• feat: out-of-order webhook delivery guard #5097 : 2 dependent PRs (#5098 , #5099 )
• feat: remove legacy project columns, old settings tables, and app_id defaults #5096 👈 (View in Graphite)
• feat: app-scoped control plane for multi-app deployments #5095
• feat: add apps table and app-scoped schema for multi-app support #5094
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.