P0-F: explicit verified SV/OR/BL Browser Read and fixed-height IED card progress underline

[masarray]

Operator evidence (2026-10-20)

Live IED Browser XCBR1 shows Status/CF populated by MMS Read or Report but substitution SV (subEna/subVal/subQ/subID), origin OR (opRcvd/opOk/tOpOk), and blocking BL (blkEna) persist as Not read. Current IedBrowserReadPlan.ReadableFc excludes all three, even in explicit Read LN. The status is not evidence of a failed wire read; these FCs were never scheduled. Reference client shows concrete values, but is only observational evidence; code is independently determined from IEC model.

• Admit only live-model-verified, read-only SV/OR/BL attributes alongside current ST/MX/CF/DC/SP/SG/SE/EX to explicit Browser read plan. No CO, MMS Write, Operate, dynamic RCB, new polling, or simulator-inferred data.
• Fixed-height, 6px reserved progress lane immediately below the IED card endpoint. Browser read toggles progress opacity only, not card overlay, layout visibility, action bar position, or card height. Discovery/connection keeps its existing BusyOverlay independently.
• Add regression for exact verified FC admission excluding CO, static XAML lane and read trigger.
• CODE only until exact SHA Windows workflows pass; FIELD verification still required for actual individual MMS Read results. Command performance remains owned by other workstream, untouched.

Stack on #634 → #630 → #628; engine pin unchanged. DRAFT, no release/merge.