Calibrate native text weight and advances

docs/phase-a-slice-plan.md

@@ -3357,6 +3357,25 @@ records, and the Godot self-test applies both modes to a real Label and checks i
 state. Validation: engine **431/431**, zero-warning Godot build, and threaded `SELFTEST OK` with
 `text-effect-modes=ok`. User visual acceptance passed on 2026-07-28.
 
+## ADV font weight and advance calibrated (2026-07-28)
+
+A disposable Windows GDI oracle measured six representative strings and the grayscale `魔` glyph
+against Godot's actual `msmincho.ttc`/`msgothic.ttc` presentation. Regular 24px Mincho and 16px Gothic
+advances match exactly, so neither face receives speculative horizontal scaling. The former
+`VariationEmbolden=1.2` overshot native weight-700 glyph coverage by 44% while remaining up to 9 pixels
+narrow across a complete sample string.
+
+The bold variation now uses measured `VariationEmbolden=0.53` plus one pixel of glyph spacing. Its
+grayscale coverage is within 0.3% of GDI and the six measured string widths are within 0..3 pixels.
+The shared style path also compensates for Godot reporting the two fonts' line boxes one pixel taller
+than AGE's explicit requested heights, preserving native total line advance during wrapping. The Godot
+self-test checks the calibrated variation and both 24px/16px spacing examples.
+
+Validation: engine **431/431**, zero-warning Godot build, and threaded `SELFTEST OK` with
+`font-calibration=ok`. The probes were deliberately disposable; the canonical measurements live in
+`docs/engine-re.md` rather than adding a Windows-only runtime/tool dependency. User visual acceptance
+passed on 2026-07-28.
+
 ## Persistence native-format reconnaissance complete (2026-07-24)
 
 The deferred save/profile ownership question now has a compatibility-mode answer. The remaining native