GetProjectPathEx returns REAPER's recording path (never empty); EnumProjects
returns the .rpp path (empty when unsaved) — the correct signal. Bank now
derives from the .rpp parent so it sits alongside the project file. Render
progress window documented as inherent to REAPER offline render.
RENDER_FORMAT now uses the base64 float-WAV config (raw bytes were rejected
into a 16-bit/44.1 fallback); RENDER_SRATE pinned to the project rate.
Unsaved projects prompt Save then refuse if cancelled — no default-location
fallback. Harden deriveBankPaths against empty projectDir.
ICaptureBackend/CaptureRequest seam + OfflineRenderBackend driving snapshotted
RENDER_* with dither/normalize forced off for bit-identical output, RenderFailed
via filesystem check, and a pure capture_paths lib with tests. Spike action registered.
daniel