Leading digits removed from mountpoint names

[lachlan-ng]

Describe the bug
Leading digits in mountpoint names are being removed, which results in site-specific options listed under receiver_options not being applied.

To Reproduce
Steps to reproduce the behavior:

1. Use a mountpoint with a leading digit as input GNSS observations inputs:gnss_observation:rtcm_inputs:
   a. e.g. 3WKB00AUS0.
2. Set some site specific options under receiver_options:3WKB:.
   a. e.g. apriori_position: [-4079562.8919, 3142464.0684, -3750920.6430]
3. Run the PEA.
4. Observe warning in stdout: Warning: No receiver apriori position found for 3WKB, and no approximate position or receiver/antenna metadata is written to output RINEX.

Expected behavior
Site-specific options to be applied to the receiver.

Configuration files
See YAML example below.

Operating environment (please complete the following information):

• OS: Ubuntu 25.04
• Version of Ginan: untagged-7a72b4b-dirty (Docker image: gnssanalysis/ginan:7a72b4b)
• Library used (Boost, Eigen, ...)

Additional context
Workaround is to use the truncated site name under receiver_options (e.g. WKB), this applies options correctly.

YAML example:

inputs:
  inputs_root: /ginan/data/products/
  atx_files: [igs20.atx]
  egm_files: [tables/EGM2008.gfc]
  igrf_files: [tables/igrf13coeffs.txt]
  erp_files: [finals.data.iau2000.txt]
  planetary_ephemeris_files: [tables/DE436.1950.2050]

  troposphere:
    gpt2grid_files: [tables/gpt_25.grd]

  tides:
    ocean_tide_loading_blq_files: [tables/OLOAD_GO.BLQ]
    atmos_tide_loading_blq_files: [tables/ALOAD_GO.BLQ]
    ocean_pole_tide_loading_files: [tables/opoleloadcoefcmcor.txt]
    ocean_tide_potential_files: [tables/fes2014b_Cnm-Snm.dat]

  snx_files: [igs_satellite_metadata.snx]

  satellite_data:
    satellite_data_root: ntrip://<USER>:<PASS>@ntrip.data.gnss.ga.gov.au:2101
    rtcm_inputs:
      ssr_antenna_offset: APC
      rtcm_inputs:
        - BCEP00BKG0
        - SSRA00BKG0

  gnss_observations:
    gnss_observations_root: ntrip://<USER>:<PASS>@ntrip.data.gnss.ga.gov.au:2101
    rtcm_inputs:
      - ALIC00AUS0
      - 3WKB00AUS0

satellite_options:
  global:
    models:
      pos:
        enable: True
        sources: [SSR]
      clock:
        enable: True
        sources: [SSR]

outputs:
  outputs_root: /ginan/data/outputs/<CONFIG>
  trace:
    output_receivers: True
    output_network: True
    level: 4
    receiver_filename: <CONFIG>_station.TRACE
    network_filename: <CONFIG>_network.TRACE

  rinex_obs:
    output: True
    filename: <CONFIG>-<RECEIVER>-<SYS>O.rnx

  metadata:
    config_description: bug

receiver_options:
  ALIC:
    receiver_type: "SEPT POLARX5"
    antenna_type: "TWIVC6050       NONE"
    apriori_position: [-4052051.7513, 4212836.1846, -2545106.0112]

  3WKB:
    receiver_type: "TPS NET-G5"
    antenna_type: "TPSG5_A1        NONE"
    apriori_position: [-4079562.8919, 3142464.0684, -3750920.6430]

processing_options:
  process_modes:
    ppp: True

  epoch_control:
    require_obs: True
    epoch_interval: 1
    max_rec_latency: 1

  gnss_general:
    sys_options:
      gps:
        process: True
        code_priorities: [L1W, L1C, L2W]