Add project name field to ComputeSessionNode (backend + frontend)

## Problem

`ComputeSessionNode` only exposes `project_id` (UUID), making it impossible to display the project name in the frontend without a separate query. Admin session list shows raw UUIDs instead of human-readable project names.

## Root Cause

Same pattern as FR-2371. The `ComputeSessionNode` type does not resolve the project name, unlike the newer `SessionV2` type which correctly exposes `project: ProjectV2`.

## Suggested Fix Direction

**Backend**: Add `project_name: String` field to `ComputeSessionNode` resolver.

**Frontend**: Update admin session list components to use the new field.

## Related Files

- `data/schema.graphql` — ComputeSessionNode type definition
- Admin session list components

## Related Issues

- FR-2371 (same pattern for Endpoint)
- FR-2370 (related scope filtering issue)

JIRA Issue: FR-2368