Add TailMode{None,Auto,Manual} + derived -72dB TRIMEND + 8s cap in render_settings;
wire into OfflineRenderBackend with snapshot/restore of the tail settings; add
CAPTURE_ITEM_TAIL/CAPTURE_TRACK_TAIL variant actions (plain actions stay exact-bounds).
Capture is now item + track only (master removed as a scope; still bypassed
as out-of-scope chain). Realtime records the selected track's own output via
per-track post-fader sends into a hidden temp track, fixing the silent file.
Replace the four capture modes with item/track/master scope actions. Each infers
its range (razor-else-time) and enforces FX scope via non-destructive
FX-bypass-around-render (RAII I_FXEN snapshot/restore over ancestors + master).
Corrects the defect of items captured through parent FX.
Four wet capture actions route to OfflineRenderBackend (snapshot/restore
RENDER_*, 32-bit float), produce a Sample, add to the bank, persist. Pure
render_settings maps source mode to RENDER_SETTINGS and parses P_RAZOREDITS
(tested). No arrange insertion. True dry deferred to M10.
daniel