Move the AUTO_ADD_OVERWRITE_OLDEST assignment to after _store->loadPrefs()
so existing bots with autoadd_config=0 saved on flash get the bit set on
every boot. Previously the assignment was in the constructor (before
load), so loadPrefs() would overwrite our default with the persisted
zero, meaning the fix only took effect on factory-fresh prefs.
- All self-advert paths (CMD_SEND_SELF_ADVERT, CMD_EXPORT_CONTACT,
MyMesh::advert()) now use bot advert name with [MCBOT] suffix when
bot_prefs.enabled, via new getAdvertNodeName() helper
- Initial flood advert at 120s after boot instead of 24h, so other
nodes see [MCBOT] in the contact name shortly after the bot boots
- AUTO_ADD_OVERWRITE_OLDEST set by default on CMESH_BOT builds, so
bots don't silently stop accepting contacts when the table fills
Patches 0001-0005 re-exported (cosmetic series-count bump 1/5 -> 1/6).
