Align Android build guidance with Gio

APK.md

@@ -23,10 +23,17 @@ Installed machine prerequisites expected by this repo:
 - `android-sdk-build-tools`
 - `android-platform-35`
 - `android-sdk-platform-tools`
-- JDK 17 or newer
+- a working JDK install
 
 The repo tracks `gogio` as a Go tool, so the build runs through:
 
 ```sh
 go tool gogio -target android ...
+
+Note:
+
+- Gio's Android doc currently references Java 1.8, but the Android build-tools
+  installed on this machine (`d8` from build-tools 37) do not run on Java 8.
+- In this environment, KeePassGO's APK build requires a newer JDK runtime on
+  `PATH`, which is why the repo defaults `JAVA_HOME` to `/usr/lib/jvm/java-25-openjdk`.
 ```

Makefile

@@ -10,7 +10,7 @@ ANDROID_TARGET_SDK ?= 35
 
 .PHONY: apk
 apk:
-	@test -x "$(JAVA_HOME)/bin/java" || { echo "JAVA_HOME must point to a JDK 17+ install"; exit 1; }
+	@test -x "$(JAVA_HOME)/bin/java" || { echo "JAVA_HOME must point to a working JDK install"; exit 1; }
 	@test -d "$(ANDROID_SDK_ROOT)" || { echo "ANDROID_SDK_ROOT must point to an Android SDK install"; exit 1; }
 	@test -d "$(ANDROID_NDK_ROOT)" || { echo "ANDROID_NDK_ROOT must point to an Android NDK install"; exit 1; }
 	@test -x "$(ANDROID_SDK_ROOT)/cmdline-tools/latest/bin/sdkmanager" || { echo "Android SDK cmdline-tools are missing"; exit 1; }

main.go

@@ -1657,7 +1657,7 @@ func (u *ui) noteCurrentVaultPath() {
 func (u *ui) layout(gtx layout.Context) layout.Dimensions {
 	// Clear the full frame explicitly so mobile surfaces don't start from an
 	// unpainted black buffer before nested background widgets run.
-	paint.Fill(gtx.Ops, bgColor)
+	paint.FillShape(gtx.Ops, bgColor, clip.Rect{Max: gtx.Constraints.Max}.Op())
 	u.syncHostedAPI()
 	u.filter()
 	u.processShortcuts(gtx)