fix: layer GUID-primary project identity so reopened/new projects reload the bank

classifyProjectTransition now checks the stored GUID first, then the pointer,
fixing the w10 regression where a recycled ReaProject* address stopped the bank
reloading. poll()'s fork re-GUID gate is bound to !sameProjectObject. Full
transition matrix pinned in tests.

src/persist.h

@@ -53,13 +53,14 @@ inline constexpr const char* kProjExtGuidKey = "project_guid";
 //   * project load       -> load the index from ext state, resolve bank paths
 //   * Save-As (new dir)   -> relocate the bank folder under the new .rpp
 //
-// Identity rests on the live ReaProject* pointer FIRST (a genuine Save-As is one
-// object saved to a new path — same pointer; a tab-switch/open is a different
-// object), with a minted GUID as a SECONDARY signal to survive pointer *reuse*
-// (REAPER recycles a closed project's address). The pointer is what distinguishes
-// a Save-As from a switch between two FORKED siblings that share a copied GUID on
-// disk (the W10 data-integrity defect: dropping the pointer let a fork tab-switch
-// masquerade as a Save-As and clobber a bank).
+// Identity is layered GUID-PRIMARY: the minted GUID (content-based identity of
+// record, immune to REAPER recycling a closed project's ReaProject* address) is
+// checked FIRST, and the live pointer disambiguates only the same-GUID case — a
+// forked sibling (same GUID, different object -> Load) vs a genuine Save-As (same
+// GUID, same object, new path -> relocate). GUID-first catches pointer recycling
+// (a reopened/new project reusing the previous address with a different GUID — the
+// W12 defect that stopped the bank reloading); the pointer catches forks (Save-As
+// copies our GUID onto a distinct object — the W10 defect that clobbered a bank).
 //
 // The bank itself is exposed for the capture/action layer to mutate; persist
 // only reads it on save and replaces it on load.
@@ -110,10 +111,11 @@ private:
     ViewModeModel view_;
 
     // The project identity last observed by poll(), used to detect load/Save-As.
-    // The pointer is the PRIMARY signal (same object across ticks = a candidate
-    // Save-As; different object = a switch/open, never a relocate). The GUID and
-    // path travel alongside: the GUID distinguishes pointer *reuse* and drives
-    // forked-sibling re-divergence; the path tells a Save-As from an idle tick.
+    // The GUID is the PRIMARY signal (a different stored GUID = a different project
+    // of record = Load, immune to pointer recycling). The pointer disambiguates the
+    // same-GUID case (different object = forked sibling -> Load; same object + new
+    // path -> Save-As) and drives forked-sibling re-divergence; the path tells a
+    // Save-As from an idle tick.
     // Held as void* so the header stays REAPER-free; it is a compared-only opaque
     // handle (never dereferenced), so a stale/recycled address is harmless.
     void*       lastProject_ = nullptr;   // last active ReaProject* (opaque; compare only)