ffmpeg-v4l2-request-fourier: route H.264 chroma DC Hadamard through daedalus-fourier (0011)

Substitutes H264DSPContext.chroma_dc_dequant_idct in the 4:2:0 /
bit_depth=8 init path with a wrapper that composes the daedalus
chroma DC Hadamard primitive (daedalus-fourier PR #25) with the
qmul scaling FFmpeg's reference does in one fused function
(h264idct_template.c::ff_h264_chroma_dc_dequant_idct).

Algorithm per H.264 §8.5.11.1 / §8.5.11.2:
  1. Extract 4 DCs from the scattered positions in the per-MB
     coefficient buffer (stride=32, xStride=16)
  2. 2x2 Hadamard transform (daedalus primitive)
  3. qmul scale + >> 7, write back to original positions

Bit-exact against ff_h264_chroma_dc_dequant_idct_8_c. The Hadamard
itself is gated by the fourier PR #23 7-case test suite (including
the H·H = 4·I algebraic invariant), and the public-API parity
test added in PR #25 confirms the src/ symbol matches the test ref.

4:2:2 chroma stays on the in-tree ff_h264_chroma422_dc_dequant_idct_c
path — same chroma_format_idc<=1 gating shape as 0009 chroma deblock.

Pin bump: _daedalus_fourier_commit / DAEDALUS_FOURIER_COMMIT bumped
to b9f9ff2a (post-PR #25) so the build picks up the public
daedalus_h264_chroma_dc_hadamard_2x2 symbol.

Verified the patch applies cleanly on top of 0001-0010 against the
pinned upstream commit b57fbbe5 on hertz.

arch/ffmpeg-v4l2-request-fourier/PKGBUILD

@@ -30,7 +30,7 @@ epoch=2
 # daedalus-fourier pin.  209a421 = PR #2 merge (Phase 8c — public API
 # gains daedalus_recipe_dispatch_h264_qpel_mc20 + DAEDALUS_KERNEL_H264_QPEL_MC20).
 # Cycle 9 closes the libavcodec.so substitution arc started at cycle 6.
-_daedalus_fourier_commit='209a4218bcb98b91c04f07ad61513bb04adb13ad'
+_daedalus_fourier_commit='b9f9ff2a89c068aea54dcb52b543afddad28311e'  # PR #25 — public chroma DC Hadamard symbol
 pkgdesc='FFmpeg with V4L2 Request API hwaccel (Rockchip / Allwinner stateless decode)'
 arch=('aarch64')
 url='https://github.com/Kwiboo/FFmpeg'
@@ -97,8 +97,9 @@ source=("git+https://github.com/Kwiboo/FFmpeg.git#commit=${_commit}"
         '0007-h264-qpel-mc20-daedalus-fourier.patch'
         '0008-h264-deblock-luma-h-daedalus-fourier.patch'
         '0009-h264-deblock-chroma-daedalus-fourier.patch'
-        '0010-h264-deblock-luma-intra-daedalus-fourier.patch')
-sha256sums=('SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP')
+        '0010-h264-deblock-luma-intra-daedalus-fourier.patch'
+        '0011-h264-chroma-dc-hadamard-daedalus-fourier.patch')
+sha256sums=('SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP' 'SKIP')
 
 pkgver() {
   cd "${_srcname}"
@@ -119,6 +120,7 @@ prepare() {
   patch -Np1 -i "${srcdir}/0008-h264-deblock-luma-h-daedalus-fourier.patch"
   patch -Np1 -i "${srcdir}/0009-h264-deblock-chroma-daedalus-fourier.patch"
   patch -Np1 -i "${srcdir}/0010-h264-deblock-luma-intra-daedalus-fourier.patch"
+  patch -Np1 -i "${srcdir}/0011-h264-chroma-dc-hadamard-daedalus-fourier.patch"
 }
 
 build() {