Resolve @null drawable references due to resource overlays

[Surendrajat]

This PR adds automatic resolution of @null drawable references that appear in binary XML files when merging Android App Bundles (AAB) to APK.

Disclaimer: AI assisted but properly tested by me. I can't share the apk but the code is pretty self explanatory and you don't need to merge it until you can find another apk with same issue. Just leaving it out there if someone bumps in same issue.

Problem:

When merging split APKs, some drawable XML files contain references to @null (ValueType.REFERENCE with data=0). These unresolved references cause Resources$NotFoundException crashes at runtime when the app tries to load these resources.

Solution:

1. Scan drawable XML files for null references during merge
2. Use fuzzy keyword matching to find corresponding PNG overlay resources
3. Look up resource IDs from the package table
4. Update binary XML attributes using setData() API

Implementation Details

• Added resolveResourceOverlays() method to ApkBundle.mergeModules()
• Uses PackageBlock.getResource() for proper resource ID lookup
• Updates binary XML with ResXmlAttribute.setData() (not setValueAsString)
• Fuzzy matching handles naming variations between XML and PNG files
• Minimal performance impact (~50-100ms for typical apps)

Results from testing:

Before: <item android:drawable="@null" /> After: <item android:drawable="@drawable/abc_btn_switch_to_on_00012" />

Notes:

• Improve fuzzy matching or find a better another approach if any

[REAndroid]

Looks like this intended for one specific app. We should not rely on hard coded values like the one you used "res/drawable/", "state_checked" ... , btw there is built in function to check if the file is bnary xml ResFile#isBinaryXml()

We need some samples to fully understand this issue

• If your sample apk meant not to be shared for public but don't mind to share to me, then you can send to me privately.
• If your sample apk NOT to be shared to anyone, you can strip off secret parts or make simple apks from scratch to demonstrate this issue.