iOS: don't upload the RR73 sign-off as a locator to PSKReporter

[patrickrb]

Summary

The iOS PskReporter.makeSpot reported a decode's senderLocator whenever the decoded grid field was >= 4 characters. The FT8 end-of-QSO roger-73 report "RR73" is a 4-char Maidenhead look-alike (R,R are valid A–R field letters; 7,3 valid digits), so the decoder copies it into grid via looksLikeGrid — and every decoded RR73 was then spotted to the global PSKReporter database as locator "RR73", a phantom Arctic coordinate (83.5°N, 175°E).

This is the iOS side of the same defect fixed on Android in PR #612 (PskReporterSender.reportableLocator).

Root cause

Per the FT8 protocol, "RR73" is packed as the roger-73 report, never as a grid — no compliant transmitter means grid RR73. The rest of the Kit already recognizes this:

• gridToLatLon (Util.swift:63) returns nil for "RR73"/"RR" to avoid a phantom map pin.
• QsoEngine classifies an incoming "RR73" as the .rr73 sequencer stage (QsoEngine.swift:348-358).

PskReporter.makeSpot (PskReporter.swift:65) was the one consumer that used a naive length check instead, so it leaked RR73 into the shared spot DB — polluting an ecosystem resource and breaking WSJT-X interop.

Fix

Extracted a pure reportableLocator(_:) helper that requires a >= 4 char locator and rejects the "RR73" sign-off (case-insensitive), and gated makeSpot's senderLocator on it. Well-formed grids (FN42, IO91wm, …) are unaffected — byte-identical spots.

Testing performed

• Added PskReporterTests cases: reportableLocator accepts real grids, rejects short tokens ("", "FN", "RR") and the RR73 sign-off (RR73/rr73/Rr73); and a makeSpot case asserting an RR73-grid decode is still spotted (the call is real) but with a nil locator.
• Ran the real XCTest suite for PskReporter.swift in isolation on Linux via SwiftPM: 24 tests pass. Verified red→green — reverting the helper to the old length-only check fails 4 cases.
• Note: a whole-module swift test on Linux is currently blocked by an unrelated Apple-only import Network in WsjtxUdpService.swift; the Foundation-only PskReporter source + its tests were exercised standalone.

Risk assessment

Very low. Single, focused policy change on a pure function; the only behavioral difference is that a locator equal to "RR73" is now omitted (as it already is everywhere else in the app). No protocol/encoder/DSP changes; well-formed decodes produce identical spots.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 36.68%. Comparing base (c1696cb) to head (73d15b2).

Additional details and impacted files

@@             Coverage Diff              @@
##                dev     #615      +/-   ##
============================================
+ Coverage     36.62%   36.68%   +0.06%     
  Complexity      197      197              
============================================
  Files           216      216              
  Lines         26885    26912      +27     
  Branches       3294     3294              
============================================
+ Hits           9847     9874      +27     
  Misses        16811    16811              
  Partials        227      227              

Flag	Coverage Δ
ios	96.51% <100.00%> (+0.02%)	⬆️
native	9.93% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
ios/FT8AFKit/Sources/FT8Engine/PskReporter.swift	100.00% <100.00%> (ø)
...8AFKit/Tests/FT8EngineTests/PskReporterTests.swift	100.00% <100.00%> (ø)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Copilot]

Pull request overview

This PR fixes an iOS FT8Engine PSKReporter spotting bug where the FT8 end-of-QSO sign-off token “RR73” (a 4-character Maidenhead look-alike) could be uploaded as a senderLocator, polluting PSKReporter with a phantom locator.

Changes:

• Added a pure helper PskReporter.reportableLocator(_:) to accept locators only when >= 4 characters and not equal to "RR73" (case-insensitive).
• Updated PskReporter.makeSpot to use reportableLocator(_:) instead of a naive length-only check.
• Added XCTest coverage for both reportableLocator(_:) and the makeSpot RR73 behavior (spot still generated, but with senderLocator == nil).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
ios/FT8AFKit/Sources/FT8Engine/PskReporter.swift	Centralizes PSKReporter locator policy in reportableLocator(_:) and prevents uploading RR73 as a locator.
ios/FT8AFKit/Tests/FT8EngineTests/PskReporterTests.swift	Adds unit tests validating the RR73 exclusion and confirming makeSpot behavior remains correct otherwise.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.