Record progressive refinement as built, and the fit view's two speed-ups

display-and-extension.md still called FR-DSP-4 absent, and
frame-budget.md ended its reading at "satisfied vacuously". 0.15.0 built
it (refine.rs, the provisional histogram, the fade), so the table row
says so, frame-budget.md gains a note under its FR-DSP-4 section, and the
register gains a status note like FR-RAW-2's and FR-UI-5's.

frame-budget.md also gains a short section with the figures 1dc7b45
(the fit view's gather cached per framing) and d430ec9 (an identity
detail pass dropped) measured, since its fit rows no longer describe the
fused path. They are quoted from those commits, on the machine they name,
and are marked as not re-run here.

docs/dev/requirements.md

@@ -667,6 +667,12 @@ asynchronously, and the proxy result remains on screen until it is ready.
 quality or resolution, refining to full quality when interaction settles. Refinement is visually
 smooth, not a jarring swap.
 
+*Status (2026-09-26).* Met in 0.15.0. A gesture renders half-resolution drafts, and the sharp frame
+lands once, 120 ms after the last movement rather than on a timer counted from the first
+(`ui/dr-ui/src/refine.rs`). While a draft is up the histogram's display reading is dimmed, since it
+describes the last settled frame; the last draft is kept over the sharp one and faded out in
+150 ms, so the refinement is not a swap.
+
 **FR-DSP-5 — Zoom and pan.** Fit, 1:1, and arbitrary zoom levels. At 1:1 and above, the pipeline
 operates on the visible crop at full source resolution.