chore(js): remove unused static logo asset (#28518)

## Summary

Removes the unused `js/packages/static/images/lightspark-logo.svg`
asset. The `@lightsparkdev/static` workspace metadata is intentionally
kept so this cleanup does not require a `js/yarn.lock` update. Fully
removing the workspace package would require a JS dependency maintainer
to recreate the lockfile change because CI gates lockfile changes by
push actor.

- The SVG is referenced nowhere in code.
- The `static/images/...` imports elsewhere resolve to
`packages/ui/src/static/`, not this package.
- The old infra sync for `js/packages/static/` was removed after the
logo moved to `sparkcore/sparkcore/static/`.

## Why this PR should exist

The asset is orphaned and creates audit noise. Removing only the unused
file is low-risk and avoids unrelated dependency-lockfile churn.

## Testing

- `yarn install --immutable`
- `rg -n
'@lightsparkdev/static|packages/static|static/images/lightspark-logo|lightspark-logo.svg'
js -g '!yarn.lock'`

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Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
GitOrigin-RevId: f19bf82424df3ddb155dcb608bf22ad9f2f75e43

Author: 2 people