Render in place: a track's output to a new sibling, source to the bench

CLAUDE.md

@@ -200,7 +200,7 @@ Plan-style docs live under `docs/`:
 
 ## The load-bearing principle
 
-**Capture and placement are separate acts.** Capturing audio writes a file to the bank and adds an index entry. It **never** puts an item in the arrange view. Placement is a distinct, on-demand action (`insert` module / `InsertMedia`). Any code path that auto-inserts a capture into the timeline violates the purpose of the tool and **must be rejected in review**.
+**Capture and placement are separate acts.** Capturing audio writes a file to the bank and adds an index entry. It **never** puts an item in the arrange view. Placement is a distinct, on-demand action (`insert` module / `InsertMedia`). Any code path that auto-inserts a capture into the timeline violates the purpose of the tool and **must be rejected in review**. A render that goes arrange → arrange, never entering the bank and never reading it (`shell/capture/render_in_place`), is a THIRD verb outside this rule rather than a softening of it — the rule binds anything that touches the bank on either side, so a bank sample may still only reach the timeline through an on-demand placement, and a capture may never grow a place step.
 
 ## Precision invariants — required before any feature ships