Address PR review: subtract-1 encoding and clamp max_hops

- Change > to >= so stored value 1 means direct/0-hop only (liamcottle)
- Clamp max_hops to 63 on write since getPathHashCount() caps at 63 (robekl)
- Update comments to reflect encoding: 0=no limit, 1=direct only, N=up to N-1 hops

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

examples/companion_radio/MyMesh.cpp

@@ -1790,7 +1790,7 @@ void MyMesh::handleCmdFrame(size_t len) {
   } else if (cmd_frame[0] == CMD_SET_AUTOADD_CONFIG) {
     _prefs.autoadd_config = cmd_frame[1];
     if (len >= 3) {
-      _prefs.autoadd_max_hops = cmd_frame[2];
+      _prefs.autoadd_max_hops = min(cmd_frame[2], (uint8_t)63);
     }
     savePrefs();
     writeOKFrame();