fix(desktop): centre the brand and project tiles on the collapsed icon rail

[pyramation]

Summary

On the collapsed rail the Wavegrid logo and the project switcher sat right of every nav icon — measured in the DOM, their glyph centres were at x=32 against the nav icons' x=24.

Both are size='lg' sidebar buttons, and that variant's collapsed p-0! never applies: it and the base group-data-[collapsible=icon]:p-2! both survive cn() (this tailwind-merge doesn't treat Tailwind v4's trailing-! important syntax as a conflict), so p-2 wins on stylesheet order. That leaves a 16px content box holding a 32px tile, which overflows to the right by exactly the padding.

Rather than fight the merge, the tile is pulled back by that padding when collapsed, and the label/chevron — which have no room on a 48px rail anyway — are hidden:

-<div className='… flex size-8 shrink-0 …'>            {/* logo / folder tile */}
+<div className='… flex size-8 shrink-0 … group-data-[collapsible=icon]:-ml-2'>
-<div className='grid min-w-0 flex-1 …'>              {/* name + subtitle */}
+<div className='grid min-w-0 flex-1 … group-data-[collapsible=icon]:hidden'>

Verified by rendering the shell against a throwaway Vite entry and reading getBoundingClientRect() for every sidebar icon: all eleven now centre at x=24. Expanded layout is unchanged.

Link to Devin session: https://app.devin.ai/sessions/972698f89f494b86828010666a002b8f
Requested by: @pyramation

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