Redact tokens, passwords and device codes from credential ToString [patch]

[matt-edmondson]

Fixes #169

What changed

HostingCredential and GitHubDeviceCode are records, and the compiler-generated ToString() printed every property. Logging a credential, interpolating it into a string, or putting it in an exception message therefore wrote a live GitHub or Azure DevOps token in plain text.

• HostingCredential.ToString(): prints Token and Password as *** when they are set and blank when they aren't, the same way a record prints a null member. Kind and Username are still shown.
• GitHubDeviceCode.ToString(): redacts DeviceCode, which is the value the token poll exchanges for a credential. UserCode, VerificationUri, ExpiresIn and Interval are still shown.
• Redacted.Of: a new internal helper that holds the placeholder, so both types print it the same way.

Both types override ToString instead of PrintMembers. The repo's analyzers report a private PrintMembers on a sealed record as unused (IDE0051, as an error), even though the compiler calls it. The output format still matches the compiler's Name { A = …, B = … } shape.

Equality, with and the properties themselves are unchanged. The [DebuggerDisplay] the issue lists as optional isn't added: the debugger's summary line already uses the overridden ToString.

Tests (CredentialRedactionTests)

Five new tests cover a token credential, a bearer credential, a username/password credential, string interpolation and a device code. Each one asserts that the secret doesn't appear in the output and that the diagnostic fields do. With the two overrides reverted, all 5 fail. With them, the full suite passes (779/779).

🤖 Generated with Claude Code

https://claude.ai/code/session_01Rt1SUkG3bsTZEWbmGirSx3

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[matt-edmondson]

In run 37870035724, Cross-Platform Tests / Test on macos-latest was cancelled at the 20-minute limit. Restore and build succeeded; the Test step was still running when it was cut off.

The diff only overrides ToString() on two records, which is unlikely to cause a hang. The same commit passed ci / .NET / Test on macos-latest in about 2 minutes, along with every other Test job. The identical Cross-Platform job on #201 also passed on macOS minutes earlier. This looks like a stuck macOS runner or test host, not this change.

I'm re-running the failed job once. If it hangs again, I'll treat it as real and investigate.

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