Q-W6: registration table (OCP) in main.cpp; bank verbs -> shell/bank_ops(Session&); persist.h + wav_trim + namespaces.h shims deleted; 61/61

capture.h realtime seam split to capture_realtime_shell.h; GetProjExtState grow-loop rehomed to core/wire/ext_state_read; stale persist.cpp/bank_panel.cpp comment refs fixed; CLAUDE.md persist/bank_book/actions bullets updated. Command-id suffixes, display phrases, and undo labels byte-identical.

src/ext_keys.h

@@ -1,6 +1,6 @@
 #pragma once
 // ext_keys — the SINGLE SOURCE OF TRUTH for the "reasampler" project ext-state
-// namespace + key names, shared by the extension (writer, via persist.h) and the
+// namespace + key names, shared by the extension (writer, via shell/persist) and the
 // VST3 instrument (reader, via the bridge). Both sides include this header so the
 // wire contract cannot drift between the two artifacts (the S4 reviewer flagged the
 // spike's duplicated constants as a drift risk).
@@ -12,7 +12,7 @@
 // either SDK.
 //
 // FOREVER-STABLE once shipped: these strings key every already-saved project's
-// stored state. Changing any of them orphans that state. See persist.h for the
+// stored state. Changing any of them orphans that state. See shell/persist/ext_state_io.h for the
 // per-key retirement / migration semantics — this header only owns the spellings.
 
 #include "core/version/app_version.h"
@@ -29,7 +29,7 @@ namespace reasampler {
 inline const char* kProjExtNamespace() { return version::extStateNamespace().c_str(); }
 
 // The multi-bank key: the whole serialized BankBook (pool + named banks). This is
-// the key the VST3 instrument reads to see the live bank (read-only, S4). persist.h
+// the key the VST3 instrument reads to see the live bank (read-only, S4). ext_state_io
 // documents its authority + the legacy-key migration around it.
 inline constexpr const char* kProjExtBanksKey = "banks";