uraniborg/Hubble: Distinguish preinstalled vs updated system apps.

[billy-lau]

Add isUpdatedSystemApp to PackageMetadata to differentiate between pristine factory preinstalled packages residing in the system image and updated system applications installed in /data/app that shadow the OEM image binary. Bump Hubble to version 2.1.0 (versionCode 11), update Gradle wrapper and AGP dependencies, pin the Gradle distribution checksum, and document classification semantics for both APKs and APEX/Mainline modules.

uraniborg/AndroidStudioProject/Hubble/app/src/main/java/com/uraniborg/hubble/:

• PackageMetadata.java: added isUpdatedSystemApp boolean field and populated it from ApplicationInfo.FLAG_UPDATED_SYSTEM_APP.
• MainActivity.java: updated VERSION constant to 2.1.0.

uraniborg/AndroidStudioProject/Hubble/app/build.gradle:

• bumped versionCode to 11 and versionName to "2.1.0".

uraniborg/AndroidStudioProject/Hubble/build.gradle:

• updated Android Gradle Plugin (AGP) from 9.3.2 to 9.4.0.

uraniborg/AndroidStudioProject/Hubble/gradle/wrapper/gradle-wrapper.properties:

• updated Gradle wrapper distribution from 9.5.0 to 9.6.0.
• pinned distributionSha256Sum for supply chain verification and tamper resistance, with inline wrapper upgrade instructions requiring the checksum.

uraniborg/VERSION:

• bumped version to 2.1.0.

uraniborg/docs/hubble_results.md:

• documented isUpdatedSystemApp property under Installed Packages.
• updated isPreinstalled description.
• added preinstalled_packages.txt component entry, clarifying that it includes both factory pre-installed and updated system applications.
• added 5-state package classification matrix under Interpretation mapping isPreinstalled, isUpdatedSystemApp, isApex, and installLocation.
• documented measurement caveats for updated system APKs in /data/app (shadowing OEM factory binaries).
• documented APEX/Mainline update semantics: FLAG_UPDATED_SYSTEM_APP is APK-only; factory compressed APEX (.capex) decompresses at boot into /data/apex/decompressed/ and hard-links into /data/apex/active/ preserving the .decompressed.apex suffix; disambiguation between factory modules and post-setup OTA updates keys on the filename suffix (.decompressed.apex vs .apex) rather than directory alone.

uraniborg/docs/hubble_setup.md:

• added command-line build instructions via ./gradlew assembleDebug.
• added section on upgrading Gradle wrapper and verifying distribution checksums, noting the TOFU caveat when piping curl.

Test: Manual.
- Built successfully with ./gradlew assembleDebug and verified checksum pin.
- Inspected connected Pixel device (adb shell dumpsys package, pm list packages)
and verified factory .capex decompress paths, flags (FLAG_UPDATED_SYSTEM_APP == 0),
and .decompressed.apex suffix against real dumps.

Change-Id: I1497c6a7f1c8362e87321ba5d4879b267d9bf26d