S4 Tier 0: the bank plays — VST3 marshals MIDI to the S3 core, reads the live bank + resolves WAV the M4 way, mono downmix, lock-free load handoff, LICE sample-pick

src/ext_keys.h

@@ -0,0 +1,38 @@
+#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
+// 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).
+//
+// PURE HEADER: NO REAPER types, NO VST3 types, NO SWELL, NO vendor/ includes. Just
+// string constants, so both the REAPER-facing persist shell and the SDK-facing VST
+// bridge can include it without pulling 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
+// per-key retirement / migration semantics — this header only owns the spellings.
+
+namespace reasampler {
+
+// The ext-state namespace all ReaSampler project state is stored under.
+inline constexpr const char* kProjExtNamespace = "reasampler";
+
+// 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
+// documents its authority + the legacy-key migration around it.
+inline constexpr const char* kProjExtBanksKey = "banks";
+
+// The retired legacy single-bank key (read once on load to migrate into the pool).
+inline constexpr const char* kProjExtIndexKey = "bank_index";
+
+// The Design-View model key.
+inline constexpr const char* kProjExtViewKey = "view_state";
+
+// The docked panel's tail-setting key.
+inline constexpr const char* kProjExtTailKey = "tail_setting";
+
+// The per-project minted-GUID identity key.
+inline constexpr const char* kProjExtGuidKey = "project_guid";
+
+}  // namespace reasampler