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/ui/commands/tests/commands.spec.ts

@@ -304,7 +304,7 @@ describe('CommandService', () => {
 
     const lifecycle = lifecycleOf(agent)
     expect(lifecycle).toMatchObject([
-      { type: 'command/run', data: { name: 'deploy', line: '/deploy now', source: { kind: 'user' } } },
+      { type: 'command/run', data: { name: 'deploy', args: ' now', source: { kind: 'user' } } },
       { type: 'command/done', data: { kind: 'success', text: 'deployed' } },
     ])
     const ids = lifecycle.map(event => (event.data as { commandId: string }).commandId)