Q-W2 review follow-ups: anon-namespace TU-private panel helpers, fix stale bank_panel.cpp comments, correct shim-transitivity claim

Wraps ~50 file-local helpers across all eight panel TUs in namespace{} (dissolves the menuAppend default-arg ODR trap); zero behavior change, 60/60 green.

src/shell/panel/panel_render.cpp

@@ -23,6 +23,8 @@
 
 namespace reasampler::panel {
 
+namespace {
+
 // --- Drawing: thumbnails (via the kit's shared drawWaveform since FA3) ---------
 
 // Draws the L7 decorative metadata overlay on a card: bars.beats.subdivisions bottom-LEFT
@@ -506,6 +508,8 @@ std::string activeBankName() {
     return bk ? bk->displayName : std::string(kPoolBankName);
 }
 
+}  // namespace
+
 // --- Full paint ---------------------------------------------------------------
 
 void paintPanel(HWND hwnd, HDC hdc) {