Q-W3: main.cpp → pointers+entry+dispatch via 4 capture hoists; one pure wav_codec RIFF owner; ICaptureBackend deleted; capture_realtime rename + finalize split; shared stampCaptureSample; makeUniqueTag gains monotonic counter (fixes same-second batch collisions). 60/60 green.

CONTEXT-ARCHIVE.md

@@ -25,8 +25,10 @@ Pure (no REAPER types, fully unit-tested):
   format, so this is simpler, testable, and dependency-free.
 
 REAPER-facing:
-- `capture` — the `ICaptureBackend` interface plus `OfflineRenderBackend` and
-  `RealtimeRecordBackend`. Input: a `CaptureRequest` (capture scope — item or
+- `capture` — two CONCRETE backends, `OfflineRenderBackend` (synchronous) and
+  `RealtimeRecordBackend` (async begin/tick/abort); no shared interface (the
+  former `ICaptureBackend` was deleted in Q-W3 — T4-26: one deriver, zero
+  polymorphic call sites). Input: a `CaptureRequest` (capture scope — item or
   track, time range, tail, SR/bit-depth/channels, output path). Output: a finished
   file + a populated `Sample` handed to `bank_model`. Capture is always wet; the FX
   *scope* (not a wet/dry dial) is the control — the pure `render_settings` module