refactor: structured command/run payload {commandId, name, args, source}

The line field is deleted (pre-release, no shim): name and args are
parseCommand's own split — name plus verbatim rawInput with its separator
whitespace — so a consumer (a projection unit folding its own command
records, a rich command card) never re-parses a line. CommandNode mirrors
the split (name/args, both null on a run-less cross-window node); the
generic card rebuilds its display line as /name + args. The connection
fixture logs the same structured payload.

packages/host/apiproxy/tests/api-proxy-commands.spec.ts

@@ -121,7 +121,7 @@ describe('command.execute', () => {
     // lifecycle pair instead of the response.
     const lifecycle = agent.session.events.filter(e => e.type === 'command/run' || e.type === 'command/done')
     expect(lifecycle).toMatchObject([
-      { type: 'command/run', data: { name: 'goal', line: '/goal ship it' } },
+      { type: 'command/run', data: { name: 'goal', args: ' ship it' } },
       { type: 'command/done', data: { kind: 'success', text: `goal:${agent.id}` } },
     ])
   })