refactor: Remove app package files from knip ignore and fix unused code

[devin-ai-integration]

Issue

• resolve: Remove TODO entries from knip.jsonc's ignore section for frontend/apps/app/ and fix the code

Why is this change needed?

Removing unused files and exports from the codebase makes it more maintainable.

What would you like reviewers to focus on?

• Verify that the removed files and unused exports are actually unused
• Check that all issues detected by knip have been addressed

Testing Verification

• Lint commands run successfully
• Knip tool runs without detecting issues in the modified files

[changeset-bot]

⚠️ No Changeset found

Latest commit: 40e40e4

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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Name	Status	Preview	Comments	Updated (UTC)
liam-app	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Apr 24, 2025 7:40am
liam-erd-sample	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Apr 24, 2025 7:40am

1 Skipped Deployment

Name	Status	Preview	Comments	Updated (UTC)
liam-docs	⬜️ Ignored (Inspect)	Visit Preview		Apr 24, 2025 7:40am

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[devin-ai-integration]

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[MH4GF]

LGTM 👍🏻

[FunamaYukina]

LGTM! Thank you!