[Tasks] Refactor NVIDIA hardware specs with typed compute capabilities (#2032)

## Summary
- Complete `NvidiaComputeCapabilities` enum with all 15 architectures
(Blackwell Ultra through Maxwell)
- Extract `NvidiaHardwareSpec`, `NvidiaComputeCapabilities`, and
`NVIDIA_SKUS` into a dedicated `hardware-nvidia.ts` file
- Type `NVIDIA_SKUS` as `Record<string, NvidiaHardwareSpec>` with
required `computeCapability`

## Test plan
- [x] TypeScript compiles cleanly (`npx tsc --noEmit`)
- [ ] Verify downstream consumers of `SKUS.GPU.NVIDIA` still work as
expected

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Moderate risk due to a public type/API surface change:
`computeCapability` is no longer part of generic `HardwareSpec`, so
downstream TypeScript consumers may need updates even though runtime SKU
data is unchanged.
> 
> **Overview**
> Moves the NVIDIA GPU SKU table out of `hardware.ts` into a new
`hardware-nvidia.ts`, introducing `NvidiaHardwareSpec` (with required
`computeCapability`) and a completed `NvidiaComputeCapabilities` enum.
> 
> Updates `hardware.ts` to reference `NVIDIA_SKUS` for `SKUS.GPU.NVIDIA`
and removes `computeCapability` from the generic `HardwareSpec`
interface, and re-exports the new NVIDIA-specific type from `index.ts`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
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[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

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Co-authored-by: Claude <Agents+claude@huggingface.co>

Author: julien-c