docs: record FB1 r11 Sample-view recompose + master gain (v8); move S-VIEW-11/12 to COMPLETED; correct stale r11 zero-state-change line

CONTEXT.md

@@ -1681,9 +1681,12 @@ S-VIEW-2 Sample face + S-VIEW-3 envelope overlay.
 > small radial knob** grouped into a fenced **knob deck**, the two **mode toggles shrink** from
 > full-width control rows to compact group-header segments, and the **inline velocity-curve box
 > is replaced by a miniature curve preview button** that summons a **full-size popup editor** —
-> freeing the **hero waveform to run full width**. Engine, params, storage, and persistence are
-> all **unchanged** — this is a pure view recomposition of existing controls (zero component-state
-> change, no new persisted fields, VST3 class UID unchanged). The **knob primitive** itself
+> freeing the **hero waveform to run full width**. The view recomposition is otherwise **parameter-
+> preserving** — existing params, their persisted seams, and the VST3 class UID are all unchanged.
+> **Exception (landed in FB1):** r11 added a post-mixer **master gain** control (MASTER group,
+> −∞…+24 dB dB-taper, per-sample ramped in the processor) backed by a new `masterGainLinear`
+> field in `ComponentState`, bumping the **envelope version v7→v8**; pre-v8 blobs lift to unity
+> gain. The **knob primitive** itself
 > (minimal arc ~6→4 o'clock, needle indicator, vertical drag) is a **separate in-flight track**;
 > this section specs the layout that consumes it. Directives (Daniel, 2026-07-27): radial knobs
 > replacing all sliders, grouped "in a reasonable way" with **the envelope controls grouped