Implement Part 4 Phase 5: Calibration UI (TapeWinNET) + calibration service layer (TapeLibNET)

[avk1im]

Scope

Implement Part 4, Phase 5 (Calibration UI) as specified in Design-RemainingAndEw.md.
Stop at Phase 5. Phases 0–4 already shipped and are validated — build on them, do not rework them.
Do NOT modify the validated low-level SCSI path (TapeDriveWin32Backend.lto-direct.cs).

Step 0 — Review and improve the design FIRST (do this before coding)

Read Design-RemainingAndEw.md fully: Phase 5 plus Parts 1–4 for context. Then cross-check
every Phase 5 assumption against the ACTUAL code before implementing — the same "As-built
notes / critical review" discipline every earlier phase followed. Specifically verify:

• The service operation pattern: ServiceOperationRequest → operation → ServiceOperationResult
  and ServiceOperationProgressHandler (as used by Backup / Restore / List).
• WpfServiceHost progress plumbing (the Backup/Restore Update…Progress methods).
• The MainWindow operation overlay (percent bar, phase text, Abort button).
• DeleteBackupSetsWindow (pattern for the confirm/warning dialog).
• IoRateSparklineControl (basis for the curve graph).
• TapeCalibrator, TapeCalibration, TapeCalibrationStore, AppSettings.Calibrations.
  Where the spec diverges from reality, correct it in code and record the divergence in the PR
  description as an "As-built notes" section.

Step 1 — Calibration service (TapeLibNET.Services)

New file TapeServiceBase.EW.cs. Mirror the existing operation triad:

• ExecuteCalibrateAsync(...) → ExecuteCalibrateCore(), with optional media eject at the end.
• Reuse ServiceOperationProgressHandler so progress plugs into the existing MainWindow overlay,
  and reuse the established cooperative Abort path bound to TapeCalibrator.IsAbortRequested.
• Bridge the semantic gap: Backup/Restore/List operate on FILES; Calibrate operates on CHUNKS.
  The Calibrate flavor of the operation classes/records maps chunks → files. Calibrate needs NO
  agent (no TOC involved).
• Backend-agnostic — drive only the public TapeDrive / TapeCalibrator surface.

Step 2 — WPF UI (TapeWinNET)

1. CalibrateWindow — confirm/warning dialog patterned after DeleteBackupSetsWindow:
   explicit destructive-operation warning (scratch cartridge required), profile summary
   (vendor / product / revision / capacity bucket), and a confirm gate.
2. Progress — reuse the MainWindow operation overlay. Add UpdateCalibrateProgress() to
   WpfServiceHost, patterned after the Backup/Restore versions: percent bar,
   bytes-written / estimated-capacity, current phase (writing to EOM, capturing EW, finalizing),
   and an Abort button.
3. CalibrationWindow (result) — show measured CapacityActual, the EW landmark, and
   EwToEomDistance; offer Save Profile (into TapeCalibrationStore via
   AppSettings.Calibrations) and immediate Apply Profile (via AddCalibration).
   Also emit a result summary to the log pane, consistent with the Backup/Restore summaries.
4. Curve graph (bonus, implement it) — a simple 2D plot of Reported → Actual remaining, with
   EW and EOM points marked. Reuse IoRateSparklineControl; lift shared drawing into a common
   base class if that simplifies both. Flip the X-axis (full capacity left → EOM right).
   PROPOSE AND IMPLEMENT a solution to magnify the small-but-critical EW→EOM tail region
   (e.g. a piecewise / non-linear X-axis or a split axis) — document your choice.
5. MVVM — a CalibrationViewModel owns the run on a background thread, marshaling
   progress/log to the UI via the established dispatch helpers; reuse WarningLevel/LogEntry
   styling for status.

Constraints & conventions

• Solution must build; ALL existing TapeLibNET / FclNET tests stay green. Add tests where the
  established pattern allows (service-layer calibrate operation especially).
• Follow the codebase's existing formatting conventions — preserve blank-line usage and
  comment placement; match surrounding style, do not reformat untouched code.
• Keep changes surgical and confined to Phase 5. Open a DRAFT pull request.

Acceptance

User can run, monitor, abort, and save a calibration entirely from the GUI; a saved profile
immediately improves the remaining-capacity figure for matching media (per the Phase 5
acceptance criteria in the design doc).