[cli] label sizes with binary units (KiB, MiB, GiB, TiB)

[erulkey]

The Drives docs describe sizes in binary units (1 TiB default, 16 TiB quota: https://vercel.com/docs/sandbox/concepts/drives), but the CLI divides by 1024 and labels the result with SI units, so the default drive prints as 1 TB:

$ sandbox drives get-or-create workspace
✅ Drive workspace ready.
   │ region: iad1
   │ max size: 1 TB
   ╰ created: 0 seconds ago

formatBytes is shared by drives, snapshots, sessions, ls and stop, so snapshot sizes and network transfer were mislabeled the same way. This changes the unit labels to KiB/MiB/GiB/TiB and leaves the math alone. Same drive from the patched build:

$ sandbox drives ls
NAME        REGION   CREATED       UPDATED       SIZE    ATTACHED SANDBOX   ATTACHED SESSION
workspace   iad1     3 hours ago   3 hours ago   1 TiB   -                  -

Not touching the max size: label wording here. It reads as a plan ceiling when it is the per-drive cap set by --max-size (a 16 TiB drive creates fine on Pro, 17 TiB gets The maxSizeBytes value must not exceed the Drive quota of 17592186044416 bytes). Happy to fold a wording change in if we want one.

Verification: pnpm vitest run in packages/sandbox, 19 files, 121 tests passed including the new test/util/output.test.ts; pnpm typecheck clean; built CLI run against Internal Playground produced the output above.