Compress native libs and support direct-boot extraction

Summary: Clawmagotchi ships 38.58 MiB of native libraries. Deflating all 103 lib/**/*.so entries reduces the release ingestion artifact from 51.03 MiB to 28.85 MiB, a 43.5% reduction.

This change:

• removes uncompress_libs_postprocessor;
• sets mos_default_native_config = False, because compressed libraries cannot use MOS direct loading;
• keeps enable_libalign = True so the ingestion alias still selects the signed, postprocessed artifact; and
• opts Clawmagotchi into SoLoader’s backup source.

Clawmagotchi is a preinstalled, direct-boot-aware HOME app. It is not installed under /data/app, and the wearable application framework normally disables the SoLoader backup source for system apps. Without the explicit opt-in, the process cannot load its compressed JNI libraries.

The SoLoader behavior is isolated behind a new opt-in flag. When enabled, SoLoader constructs BackupSoSource with an explicit store path under the device-protected context. A package-private BackupSoSource overload accepts that path and preserves it during recovery. Existing constructors and UnpackingSoSource path selection are unchanged, so other apps retain their current extraction behavior.

The opt-in also enables SOLOADER_ALLOW_ASYNC_INIT. Library extraction remains complete before SoLoader.init() returns, while the expensive fsync and clean-state write finish on SoLoader’s background sync thread.

The AOSP counterpart is D120455457. It opts this non-GMS product prebuilt out of the presigned-preprocessed check that otherwise rejects compressed JNI. The first compressed prebuilt and that AOSP flag must be integrated together:

Prebuilt	Skip flag	Result
Uncompressed	Absent	Pass
Uncompressed	Present	Fail as unnecessary
Compressed	Absent	Fail for compressed JNI
Compressed	Present	Pass

The storage tradeoff is intentional. The release APK saves about 22.18 MiB in the image and in distribution, while the extracted native cache occupies 38.80 MiB in userdata. The benefit is image and download size, not total device storage.

Coop-docs: no change (internal packaging and native-library loading; no observable screen, navigation, capability, content-description, or logging behavior).

Reviewed By: akashkalimiliMeta

Differential Revision: D120355062

fbshipit-source-id: b0dde2d11fec5b2e8d702c0f79cb5d85ecbc1d94