Phase 28B: extract Pimax registration assessment architecture

[Zaknin]

Summary

• Adds a read-only Pimax registration assessment layer that combines the existing filtered connectivity snapshot with the expanded USB/PnP enumeration snapshot.
• Adds CLI-only pimax-registration-assessment-json output with schema pimax-registration-assessment-v1.
• Preserves the existing pimax-connectivity-json / pimax-connectivity-v1 and pimax-usb-enumeration-json / pimax-usb-enumeration-v1 commands.
• Documents future recovery experiments separately without implementing recovery behavior.

Evidence basis

• Phase 28A5 classified the white-to-blue transition as statically distinguishable by the appearance of the Generic USB Hub VID_05E3/PID_0608 and Valve/Pimax-adjacent VID_28DE/PID_2101 / VID_28DE/PID_2300 records.
• Registered-ready evidence is treated as requiring Crystal runtime records such as VID_34A4/PID_0012 and EyeChip VID_2104/PID_0220, together with the filtered connectivity snapshot.
• The assessment intentionally does not claim physical LED detection.

Safety boundary

• No recovery actions, USB resets, device enable/disable, service/process control, SteamVR behavior changes, bridge protocol changes, TUI changes, or release packaging changes.
• New assessment code is pure classification plus orchestration of the existing read-only probes.

Validation

• dotnet build .\PimaxVrcSupervisor\PimaxVrcSupervisor.csproj -c Release
• dotnet test .\PimaxVrcSupervisor.Tests\PimaxVrcSupervisor.Tests.csproj -c Release (119 tests)
• dotnet build .\PimaxVrcSupervisor.ConfigEditor\PimaxVrcSupervisor.ConfigEditor.csproj -c Release
• dotnet build .\PimaxVrcSupervisor.SteamVrHost\PimaxVrcSupervisor.SteamVrHost.csproj -c Release
• cargo test --manifest-path .\PimaxVrcSupervisor.Tui\Cargo.toml (12 tests)
• python -m mkdocs build --strict
• CLI smoke: pimax-connectivity-json, pimax-usb-enumeration-json, pimax-registration-assessment-json