openhop/repeater: fixes from first real deploy on ubuntuHEADmain

- create spi/gpio groups and udev device rules (Raspberry Pi OS ships them, Ubuntu does not)
- hardware CS via spidev (cs_pin -1); a manual cs_pin on a kernel-owned CE line fails EBUSY
- align RAK6421 pin maps with upstream's hardware catalog: en_pins for the FEM enables,
  gpiod backend on chip 0 (catalog says chip 1, wrong for Pi 4)
- us RF preset is now MeshCore USA/Canada (Recommended): 910.525 / SF7 / BW62.5 / CR5
- set storage.storage_dir; omit mqtt_brokers entirely (any key enables the MQTT pusher)
- fetch radio-settings/radio-presets json into the data dir (pip omits them and the web
  setup wizard's hardware step is empty without them)
- config deployed 0660 with a vaultable repeater.security block so the daemon can persist
  credentials and re-templates no longer wipe them
- sudoers rule so the web UI can restart the service after config changes

1 files changed, 4 insertions, 3 deletions

diff --git a/openhop/repeater/vars/rf/us.yaml b/openhop/repeater/vars/rf/us.yaml
index e20b1c6..2eecc99 100644
--- a/openhop/repeater/vars/rf/us.yaml
+++ b/openhop/repeater/vars/rf/us.yaml
@@ -1,11 +1,12 @@
 ---
-# MeshCore US 902-928 MHz preset.
+# MeshCore "USA/Canada (Recommended)" community preset: 910.525 / SF7 / BW62.5
+# / CR5. The wide alternate is SF11 / BW250 / CR5.
 # WARNING: every node on your mesh MUST share identical frequency / bandwidth /
 #          spreading_factor / coding_rate. Confirm these against your local
 #          MeshCore US community settings before deploying.
 repeater_frequency_hz: 910525000     # 910.525 MHz
-repeater_bandwidth_hz: 250000
-repeater_spreading_factor: 11        # 7-12
+repeater_bandwidth_hz: 62500
+repeater_spreading_factor: 7         # 7-12
 repeater_coding_rate: 5              # 5-8
 repeater_preamble_length: 32
 repeater_tx_power_dbm: 22            # SX1262 register max; SKY66122 boosts to ~1W