* fix: accept NUL-padded RPTC callsigns in login check
Fixed-width RPTC fields may be padded with NUL (ipsc2hbp) or spaces
(MMDVM). str.rstrip() left trailing NULs so matching DB callsigns were
rejected with MSTNAK after a successful passphrase exchange.
* fix: strip NUL padding from RPTO OPTIONS in logs and storage
ipsc2hbp pads the fixed-width RPTO body with NULs; logs showed ^@ noise
and peer CALLSIGN as raw bytes on the options line. Normalize on ingest
and in redact_pass_in_options.
* fix: strip NUL padding from monitor export and shared HBP fields
Centralize fixed-width NUL/space trimming in domain helpers and use them
for dashboard_state peer fields, OPTIONS parsing, proxy self-service, and
remaining CALLSIGN log lines.
ce5rpy