Phase 29A: instrument base-station startup diagnostics

[Zaknin]

Summary

• Adds instrumentation-only base-station startup diagnostics for Supervisor Bluetooth wake stages and Configurator Scan observations.
• Writes bounded JSONL diagnostics under %LOCALAPPDATA%\PimaxVrcSupervisor\Diagnostics\BaseStations with deterministic station hashes and no full Bluetooth addresses.
• Adds scripts/collect-base-station-startup-diagnostics.ps1 to package logs, diagnostics, process state, and read-only Bluetooth adapter metadata for Phase 29B analysis.

Behavior preservation

• No base-station timing, retry, burst, payload, scan, discovery, protocol, TUI, SteamVR, shutdown, or startup behavior changes are intended.
• PowerOnCommandTimeout, retry delay, OpenVR cycles, pass counts, and command bytes remain unchanged.
• Diagnostics write failures are non-fatal.

Validation

• dotnet build .\PimaxVrcSupervisor\PimaxVrcSupervisor.csproj -c Release passed.
• dotnet test .\PimaxVrcSupervisor.Tests\PimaxVrcSupervisor.Tests.csproj -c Release passed: 126 tests.
• dotnet build .\PimaxVrcSupervisor.ConfigEditor\PimaxVrcSupervisor.ConfigEditor.csproj -c Release passed.
• dotnet build .\PimaxVrcSupervisor.SteamVrHost\PimaxVrcSupervisor.SteamVrHost.csproj -c Release passed.
• cargo test --manifest-path .\PimaxVrcSupervisor.Tui\Cargo.toml passed: 12 tests.
• python -m mkdocs build --strict passed with the existing MkDocs Material warning.
• Static scan found no device/service/process mutation APIs in the new diagnostics path; the collector uses read-only Get-PnpDevice metadata.

Interactive smoke

• Baseline startup with instrumented Supervisor: burst 1 succeeded, burst 2 succeeded, all four stations powered on.
• Supervisor diagnostics captured 1 burst started, 1 burst completed, 8 station attempts, 8 successes, 0 timeouts, and session completion.
• Instrumented Configurator Scan completed: 4 base stations found, 4 shown.
• Diagnostic package created at %TEMP%\PimaxVrcSupervisorDiagnostics\BaseStationStartup-20260616-235605.

Next phase

Phase 29B should analyze repeated base-station startup sessions and determine the discovery/readiness failure stage.