`jump_if`

Conditional jump: first matching case, else optional fallback.

{
  "type": "jump_if",
  "cases": [
    { "expr": "score > 5", "to": "good" },
    { "expr": "score > 0", "to": "ok" }
  ],
  "else": "bad"
}

[jump_if score > 5 -> good else bad]

Usually you need

Field	Type	Default	Effect
`cases`	array `{ expr, to }`	—	First truthy wins
`else`	string	—	Fallback node id

Field	Type	Default	Effect
`cases`	array	—	`{ "expr", "to" }`
`else`	string	—	Fallback
`when`	expression	—	Skip whole command when falsy