[masarray]

What changed

• Fix actual WPF root cause: the shared CommandDockTransparentHeaderExpander used an Auto-sized body inside a finite outer Dock row, letting the DataGrid overflow/clamp beneath the status bar. Use bounded Star layout, real shell-height constraints, stable resize and visible pixel-scroll virtualization.
• Expose Write DA… from the live IED Browser for a focused DO or DA; single DA or up to 16 explicitly staged DA edits with one operator confirmation, executed sequentially, not atomically.
• Use exact current live MMS directory/association type/FC admission; admit CF, DC, SP, SG, SE primitives only; never CO Operate, process ST/MX/SV, or RCB writes.
• Reuse compiled ARIEC61850 MmsClientSession single-variable Write and Read, with typed pre-read, at-most-one confirmed write per DA, exact typed readback and no automatic retry. Reuse the same native association and control-flight quarantine, preserve production engine lock.
• Add regression tests covering actual XAML template, scrollbar contract, typed ctlModel 0–4 validation, and wire safety boundaries.

Field evidence

• User screenshot: BCUGE is the selected Command Dock target; the ZIVAVR issue cannot be inferred from that screenshot alone.
• Uploaded diagnostic shows ZIVAVRLD1/ATCC1.TapChg already verified as BSC, DirectNormal, canOperate=True in that association.
• This PR performs no physical relay write and is not release-approved. A supervised ZIVAVR configuration write/typed readback FAT remains required.

Required CI before EXE

Canonical Windows Build/R7/P0/SV/COMTRADE and Windows nonrelease engine trial. Do not merge/promote automatically.

[masarray]

Typography overlap notice: Draft SMV P3 #714 directly stacks on #711/#708/#705 and includes a single App.xaml shared-resource change: AppCodeFontFamily now aliases already-embedded Inter, per operator's all-Inter requirement. #686 also changes App.xaml; future integration must use deliberate three-way resolution preserving both control-write resource additions and Inter alias. The SMV numerical/renderer changes live elsewhere. No merge was attempted.