Add scriptOnly flag to custom commands for freeform input

Problem: When you make custom commands in Bedrock's Script API, the game's command parser checks your arguments BEFORE your script even runs. This breaks commands that need to accept:

• Math expressions like "2 + 3 * (4 / 2)" - the + and * symbols get rejected

• Multi-word messages without quotes - "msg @p hello there" gets split wrong

• Symbols and special characters - !@#$ are treated as invalid

Current workarounds are bad:

• Intercepting chat messages globally - conflicts with other addons

• Forcing players to use quotes - confusing UX

• Routing through /scriptevent - breaks command naming and permissions

My solution: Add a simple "scriptOnly" flag to CustomCommand definitions.

{
  name: "my:calc",
  description: "Calculate anything",
  scriptOnly: true
}

When true, the game engine skips parsing entirely and passes the raw command string to your script. You parse it however you want.

Why this is safe:

• Works exactly like /scriptevent and chatSend (already accept raw input)

• Permission checks still run - only parsing is skipped

• Developers already handle parsing for those other APIs

• No new attack surface - the raw string path already exists

Benefits:

• Commands work as players expect

• No more parser workarounds

• Consistent with existing raw-string APIs

• Minimal engine change (just bypass a check)

This is a small, additive change that fixes a major pain point for script developers. Please consider adding it to the next API update.