[codex] Document Windows Hello PIN modality

[SirAndrosBot]

What changed

• Removed README wording that described KeePassWinHello as specifically using “pin or biometrics” and replaced it with neutral Windows Hello wording.
• Changed the persistent-key description from “signed with your biometry” to “protected by Windows Hello.”
• Added an explicit note that Windows controls which Windows Hello gestures can authorize a prompt, including PIN, fingerprint, face recognition, or other configured Hello methods.
• Added a security notice that biometric-only enforcement or PIN fallback removal must be handled in Windows Hello configuration or organizational policy, not by this plugin per prompt.

Why

Issue #50 asks for an option to remove the ability to authorize with Windows PIN while still allowing biometric Windows Hello. KeePassWinHello uses the Microsoft Passport/Windows Hello CNG provider and asks Windows Hello to require user verification. The provider surface used here does not expose a safe per-plugin switch to allow biometrics while disallowing PIN fallback.

Adding a plugin checkbox would therefore be misleading: it would imply a security guarantee the plugin cannot enforce. This PR documents the boundary clearly instead.

Refs #50

Validation

• Worker subagent for Remove ability to sign in with windows PIN #50 initially errored due account subagent usage limit, so I continued the implementation locally.
• Reviewer subagent reviewed the docs-only change and found no blocking issues.
• Applied reviewer wording feedback to avoid implying biometric-only behavior.
• git diff --check passed with only Git LF-to-CRLF working-copy warnings.
• MSBuild.exe src\KeePassWinHello.csproj /t:Rebuild /p:Configuration=Release /p:DefineConstants=MONO /p:FrameworkPathOverride=C:\Windows\Microsoft.NET\Framework\v4.0.30319 /p:ReferencePath=C:\proj\KeePassWinHello\lib passed with 0 warnings and 0 errors.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

See analysis details on SonarQube Cloud