Worker memory operations fail when memory.boxSize is configured as a string

[GaspardKirira]

The supervisor memory configuration supports boxSize as either a number or a human-readable string such as "1KB".
createMemoryPool() already resolves string values correctly through parseBoxSize(), but worker-side memory operations currently use:

Number(config.memory.boxSize)

This works for numeric values like 1024, but fails for string values like "1KB" because Number("1KB") returns NaN.
This can break worker-side ctx.write() and ctx.read() operations when the supervisor is configured with a string boxSize.
Example configuration:

createSupervisor({
  maxActors: 5,
  memory: {
    poolSize: 2,
    boxSize: "1KB",
  },
  timeouts: {
    defaultLeaseMs: 2000,
  },
});

Expected behavior:
Worker memory operations should support the same boxSize formats as createMemoryPool().

Suggested fix:
Use parseBoxSize(config.memory.boxSize) inside worker memory read/write operations instead of Number(config.memory.boxSize).
A regression test should verify that an actor can write and read shared-memory data when boxSize is configured as "1KB".