User feedback round 2 (4.5.4): no notification shown, report not
sending, no error visibility on crash. Diagnosis: APRS-IS port 14580
reachable (verified with real login test), 24580 SSL refused; login
format OK. Fixes:
- Settings dialog: "Compute passcode" button - fills passcode from
callsign via the ported 0x73E2 algorithm (user can see the result)
- Global crash handler in MainApplication: stack trace appended to
files/crash_log.txt so crashes are diagnosable (user: no crash logs
were available before)
- POST_NOTIFICATIONS runtime permission requested when enabling APRS
(Android 13+ otherwise silently hides the service notification)
- AprsIsClient: read the login response (aprsc "# logresp ...
unverified"/"Invalid") and surface the server message as the error
- AprsForegroundService: Toast on manual report result (OK / failure
with server reason)
- Strings EN/ZH/TR/IN/ID +3 keys
Verified: compileDebugKotlin all modules BUILD SUCCESSFUL,
check_strings 9 files OK.