feat(app): add basic animation with toggle :)

[ProdigyRahul]

What does this PR do?

Animations

• Smooth sidebar open/close animation (left panel slides in/out)
• Smooth review panel open/close animation (session content width transitions as panel appears/disappears)
• Smooth file tree panel open/close animation (slides in/out horizontally within the side panel)
• Smooth terminal panel open/close animation (slides up/down vertically)
• Mobile sidebar already had animations now gated by the toggle

Settings

• Added "Animations" toggle in Settings > Appearance section
• When OFF, all panels open/close instantly (original behavior)
• When ON (default), all transitions are smooth 200ms ease-out
• Persisted to localStorage like other settings

@adamdotdevin @iamdavidhill any thoughts?

Before:

2026-02-07.17-35-24.mp4

After:

Screen.Recording.2026-02-07.at.5.46.53.PM.mp4

You can toggle this effect if someone dont like it.

[github-actions]

Thanks for your contribution!

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1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

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[github-actions]

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No duplicate PRs found

[ProdigyRahul]

done @alexyaroshuk but not sure if this pr will ever get merge or response :) i am okay if adam closes this 👍🏻 this is just gonna increase the pr counts ngl