QVplayer video decoder source bundle

Runtime components:
- AndroidX Media3 1.11.1 decoder_av1 and decoder_vp9 Java/JNI wrappers, Apache-2.0.
- libvpx 1.15.2, BSD-3-Clause plus the supplied PATENTS grant.
- dav1d 1.5.4, BSD-2-Clause.
- Google cpu_features commit 4814778e45acc394b37ca0837441ad32a2305bb1, Apache-2.0.

Build tools (not included in the app): NDK 28.2.13676358, Python 3.12+, Meson
1.12.1, Ninja, CMake 3.21+, host make/C compiler and NASM 2.16.03. The official
NASM source is included and is built locally if NASM is not found on PATH.
Install Meson in a dedicated environment: python3 -m pip install meson==1.12.1

Run from any directory:
python3 rebuild_video.py --ndk /path/to/android-ndk/28.2.13676358 \
    --work /tmp/qv-video-rebuild --output /tmp/qv-video-rebuilt-jniLibs

The source archives' SHA-256 values are checked against provenance.json before
extracting. The script reproduces the native build configuration used to produce
the supplied binaries, copies the three .so files per ABI, strips unused symbols,
and verifies a minimum 16 KB ELF LOAD segment alignment. Source build paths and
host compiler/tool versions may affect byte-for-byte output hashes.

Configuration changes from the upstream Media3 default:
- VP9 high-bit-depth decoding is enabled (10/12-bit; output uses upstream JNI
  conversion/dithering support).
- SVE and SVE2 are disabled because the upstream Android.mk does not split their
  C files into feature-specific compilation units. NEON, dotprod and i8mm retain
  upstream runtime dispatch; disabling SVE does not remove codec format support.
- All binaries target Android API 26 and use -Wl,-z,max-page-size=16384.
- C++ runtime is linked statically; there is no libc++_shared.so dependency.
- dav1d tests, examples and command-line tools are disabled for the app build.

No QVplayer signing key, password, advertising ID or app-private source is included.
Exact upstream commits, source hashes, binary hashes, ELF dependency lists and
build verification scope are in provenance.json. Device decoding tests are not
performed by this source bundle; the integrating app must validate its runtime.
