fix: command op replies that said ok when nothing was done

From the review of #100:
- setMyPosition on a moving shade replies busy ("The shade is moving"),
  and setPositions with only a tilt, for a shade without one, replies
  bad request ("The shade has no tilt"). Both said ok before.
- PROTOCOL.md lists where the ops differ from the routes, and how
  sendRemoteCommand is answered.
- The LoopQueue hold comment covers protocol 2 replies and an unpair
  held through a frequency scan.
- One shadeRequestIsForGroup() for the group cases; ProtoOps shares one
  reader for "one or both" fields and one for ids, and the radio
  refused text.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/Somfy.h

@@ -105,6 +105,7 @@ class SomfyShade : public SomfyRemote, public ShadeSettings, private MotorLink,
     uint8_t getShadeId() { return shadeId; }
     // Where the shade is and where it is going.
     const ShadeBehaviour::State &state() const { return this->behaviour.state(); }
+    bool isIdle() const { return this->behaviour.isIdle(); }
     uint8_t getFlags() override;
     // Sets the setting and state bits from a saved or sent flags byte.
     void setFlags(uint8_t flags);