Modernize Windows Qt6 wallet build

doc/build-wallets.md

@@ -53,7 +53,7 @@ The wallet build is sensitive to tool version mismatches:
 
 * Native Ubuntu uses the deterministic depends Qt6, OpenSSL, Boost, protobuf,
   and supporting libraries.
-* Windows cross-target wallets currently use the existing Qt5 cross path and
+* Windows cross-target wallets use the deterministic depends Qt6 path and
   matching Qt host tools staged by depends.
 
 The helper scripts keep those rules in one place so the build is repeatable on a

doc/build-windows.md

@@ -227,9 +227,9 @@ builds and stages a matching native `protoc` when needed.
 QT NOTE
 ============================================================
 
-The current Windows cross-build helper still targets the existing Qt5 cross
-path. The native Ubuntu wallet path has moved to Qt6. Keep those paths separate
-until the Windows Qt6 cross-build is explicitly modernized and smoke-tested.
+The Windows cross-build helper targets the Qt6 depends path. Keep the helper's
+Qt host tools (`moc`, `uic`, `rcc`) staged from the matching depends build to
+avoid mixing host Qt tools with target Qt libraries.
 
 ============================================================
 END OF DOCUMENT

doc/installer.md

@@ -130,8 +130,8 @@ The installer requires these `.pc` files in `depends/<host>/(lib|share)/pkgconfi
 
 - Native Ubuntu Qt6 path: `Qt6Core.pc`, `Qt6Gui.pc`, `Qt6Network.pc`,
   `Qt6Widgets.pc`
-- Windows cross-build Qt5 path: `Qt5Core.pc`, `Qt5Gui.pc`, `Qt5Network.pc`,
-  `Qt5Widgets.pc`
+- Windows cross-build Qt6 path: `Qt6Core.pc`, `Qt6Gui.pc`, `Qt6Network.pc`,
+  `Qt6Widgets.pc`
 
 Fix by rebuilding depends with Qt enabled: