feat(commands): adopt unified command envelope — msg.origin provenance

Resolve command origin via msg.origin (registry-stamped, default parent) with a
legacy fallback to the previous payload.source/msg.source field. Feeds the
existing mode/allowedSources arbitration unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/commands/handlers.js

@@ -7,23 +7,33 @@
 function _logger(source, ctx) { return ctx?.logger || source?.logger || null; }
 function _send(ctx, ports) { if (typeof ctx?.send === 'function') ctx.send(ports); }
 
+// Resolve the command origin (control authority: parent | GUI | fysical).
+// The shared commandRegistry stamps msg.origin (default 'parent'); legacy flows
+// carried it as payload.source. Prefer the legacy field when present so existing
+// flows keep working, otherwise use the registry-stamped msg.origin.
+function _origin(msg) {
+  const p = msg && msg.payload;
+  if (p && typeof p === 'object' && typeof p.source === 'string' && p.source) return p.source;
+  return (typeof msg?.origin === 'string' && msg.origin) ? msg.origin : 'parent';
+}
+
 exports.setMode = (source, msg) => {
   source.setMode(msg.payload);
 };
 
 exports.startup = async (source, msg) => {
   const p = msg.payload || {};
-  await source.handleInput(p.source ?? 'parent', 'execSequence', 'startup');
+  await source.handleInput(_origin(msg), 'execSequence', 'startup');
 };
 
 exports.shutdown = async (source, msg) => {
   const p = msg.payload || {};
-  await source.handleInput(p.source ?? 'parent', 'execSequence', 'shutdown');
+  await source.handleInput(_origin(msg), 'execSequence', 'shutdown');
 };
 
 exports.estop = async (source, msg) => {
   const p = msg.payload || {};
-  await source.handleInput(p.source ?? 'parent', p.action ?? 'emergencystop');
+  await source.handleInput(_origin(msg), p.action ?? 'emergencystop');
 };
 
 // Legacy umbrella: payload.action selects the canonical verb.
@@ -41,7 +51,7 @@ exports.execSequenceAlias = async (source, msg, ctx) => {
 exports.setPosition = async (source, msg) => {
   const p = msg.payload || {};
   const action = p.action ?? 'execMovement';
-  await source.handleInput(p.source ?? 'parent', action, Number(p.setpoint));
+  await source.handleInput(_origin(msg), action, Number(p.setpoint));
 };
 
 exports.dataFlow = (source, msg) => {