Fix vacuous bounds test and stale/circular comments from the settle

Replace the self-comparing render-window loop with a genuinely discriminating
floor-vs-exact check; correct two stale claims; mark the Auto/Manual floor-parity
premise as unverified; drop the STARTPOS/ENDPOS comment's circular justification.

docs/VERIFICATION.md

@@ -27,7 +27,7 @@ Checks for Θ, Ξ, and Ψ work that no unit test can close. Build **Release**, i
 - [ ] One razor-union case (two disjoint areas, one track) — lands the requested window, no `ReaSampler capture failed:` line (`PLAN.md:2137`)
 - [ ] Capture an item whose extent already equals the window — still lands, unchanged (the byte-identity regression floor) (`docs/COMPLETED.md:829`)
 - [ ] **The millisecond floor — SETTLED, nothing to re-run for `TailMode::None`.** The floor lives in the custom-time-bounds field (`RENDER_BOUNDSFLAG=0`), not in the render engine. Two live 48 kHz `TailMode::None` renders on `RENDER_BOUNDSFLAG=2` (time selection, handed over via `GetSet_LoopTimeRange`) came back exact — 97627 frames against 97627 — the second over a window whose START carried a sub-millisecond remainder, with no floored model of that window able to reproduce the count. Time selection is now the only bounds mode a capture can reach; the console verdict line and the `RENDER_STARTPOS`/`ENDPOS` read-back probe that answered this are gone. Full observation: `src/core/capture/render_settings.h`'s `kRenderBoundsTimeSelection`
-- [ ] **Still open — Auto and Manual tail.** `checkRenderedBounds` judges `TailMode::None` only (Auto/Manual add frames by design), so the settled result covers those two by INFERENCE, not observation: the floor applied to the bounds identically on all three tail modes, and all three now hand the window over the same way. What would establish it: repeat an off-grid-start capture at **Manual** over a source that is loud right to the window's end, and check the landed file's frames against window + `tailMs` — a floored edge shows up in that count. **Auto** cannot be checked by count (it trims trailing silence), so it needs the null test by ear/inversion against the source instead
+- [ ] **Still open — Auto and Manual tail.** `checkRenderedBounds` judges `TailMode::None` only (Auto/Manual add frames by design), so the settled result covers those two by INFERENCE, not observation, and the inference rests on an unverified PREMISE too: that the (retired) floor applied to the bounds identically across all three tail modes, and that all three now hand the window over the same way. Neither is measured — both live short renders that settled the bounds mode were `TailMode::None`; no Auto or Manual capture has been observed at all. **On Auto/Manual, the ONLY automatic check left is the 0-byte gate (`checkRenderedFileNotEmpty`)** — there is no automatic bounds signal for those two modes at all until this bullet is closed by hand. What would establish it: repeat an off-grid-start capture at **Manual** over a source that is loud right to the window's end, and check the landed file's frames against window + `tailMs` — a floored edge shows up in that count. **Auto** cannot be checked by count (it trims trailing silence), so it needs the null test by ear/inversion against the source instead
 - [ ] `[verify — DAW]` A tail is assumed to render PAST the window end — the SDK header (`:3048`) confirms only that `RENDER_TAILMS` is a length in ms, not that it extends past the end. If that assumption is wrong, a tail capture is silently SHORTER than its window with no detector at all. Report whether either tail capture comes up short against the source
 - [ ] A refused render is kept for diagnosis at `<project folder>/reasampler_refused/` (the refusal line names the path; a failed move leaves it unindexed in the bank folder and says so). Delete the folder when done — nothing in the bank references it
 - [ ] **If a capture is refused for a short render**, report the refusal line verbatim. A message naming `floored to the millisecond` means the floor is back on a mode measured escaping it; a shortfall of one or two frames with no such sentence may be the gate's own edge-convention tolerance rather than the render (`render_window.h`'s `renderHonoredBounds`)