(fix) shell: handshake defaults width, height

[mialso]

Description:

problem: shell mode server fails to accept client connection due to required width & height int by handshakeSpawn protocol

solution: provide default width & height

other options: add protocol defaults

how to repro:

$ npm run test

# shell
    ok 1 - Server firewall allowed
    not ok 2 - server stderr: undefined Error: uint must be positive
    at validateUint (/Users/mialso/projects/hypershell/node_modules/compact-encoding/index.js:1007:11)
    at Object.encode (/Users/mialso/projects/hypershell/node_modules/compact-encoding/index.js:161:5)
    <..>
    at Protomux._oncontrolsession (/Users/mialso/projects/hypershell/node_modules/protomux/index.js:532:21)

      ---
      operator: fail
      source: |
          sp.on('error', (error) => t.fail('server error: ' + error.message))
          sp.stderr.on('data', (data) => t.fail('server stderr: ' + data))
        -----------------------------------^
        
          return sp
      stack: |
        Socket.<anonymous> (./test/helpers/index.js:79:36)
        <..>
        Pipe.onStreamRead (node:internal/stream_base_commons:189:23)
      ...

with the fix:

$ npm run test

<..>
# shell
  ok 1 - Server firewall allowed
  ok 2 - client stdout match
  ok 3 - client closed: 130
  ok 4 - server closed: 130
ok 2 - shell # time = 905.305084ms

<..>

1..4
# tests = 4/4 pass
# asserts = 20/20 pass
# time = 1216.692167ms

# ok