fix(nimble): Improve safety, fix bugs, and update docs across NimBLE examples

- Remove unused headers from examples
- Improve periodic adv/sync example functionality and readability
- Use ble_hs_id_infer_auto() instead of hardcoded BLE_OWN_ADDR_PUBLIC/RANDOM
- Add ble_hs_util_ensure_addr() calls in on_sync for proper address setup
- Use correct ext adv instance (0 instead of 1) in phy_prph, l2cap_coc, multi_conn
- Fix struct name: ble_gap_periodic_adv_enable_params -> ble_gap_periodic_adv_start_params
- Add CONFIG_BT_NIMBLE_GAP_SERVICE guards around ble_svc_gap_device_name_set
- Fix unsafe AD data parsing with bounds checks in central examples
- Fix UUID matching bugs (off-by-one loop condition and byte order) in
  phy_cent, htp_cent, and proximity_sensor_cent
- Fix ble_multi_conn_cent address type to use dynamic inference
- Remove contradictory sm_sc=0 after sm_sc=1 in ble_multi_adv
- Add CONFIG_BT_NIMBLE_EXT_ADV=y to ble_multi_adv sdkconfig defaults
- Check return values for ble_gap_set_host_feat, nimble_port_init
- Update tutorials and READMEs to match code changes

examples/bluetooth/nimble/ble_proximity_sensor/proximity_sensor_cent/main/main.c

@@ -261,10 +261,10 @@ ext_ble_prox_cent_should_connect(const struct ble_gap_ext_disc_desc *disc)
     /* The device has to advertise support for Proximity sensor (link loss)
     * service (0x1803).
     */
-    do {
+    while (offset < disc->length_data) {
         ad_struct_len = disc->data[offset];
 
-        if (!ad_struct_len) {
+        if (ad_struct_len == 0 || offset + ad_struct_len + 1 > disc->length_data) {
             break;
         }
 
@@ -276,8 +276,7 @@ ext_ble_prox_cent_should_connect(const struct ble_gap_ext_disc_desc *disc)
         }
 
         offset += ad_struct_len + 1;
-
-    } while ( offset < disc->length_data );
+    }
 
     return 0;
 }