ffmpeg-v4l2-request-fourier: export ff_h264_set_mb_inspect_cb (0016 amend, PKGREL 15)

The 0016 patch declared ff_h264_set_mb_inspect_cb in h264dec.h and
defined it in h264_mb.c, but didn't touch libavcodec/libavcodec.v.
FFmpeg's default version script exports only `av_*`, `avcodec_*`,
`avpriv_*`, and `avsubtitle_free`; everything else is hidden as LOCAL
behind a `*` glob.  Result: `nm -D libavcodec.so.62 | grep
ff_h264_set_mb_inspect_cb` returned nothing → dlsym() returned NULL.

Static-link CLI consumer (daedalus_decode_h264) was unaffected
because static linking doesn't care about symbol visibility.  The
daedalus-v4l2 daemon shadow_decoder path (PR-Q3a.1) dlopens
libavcodec.so.62 and resolves the callback via dlsym — that needs
the symbol exported.

Fix: add ff_h264_set_mb_inspect_cb to the global list in
libavcodec/libavcodec.v.  Single-line addition to the 0016 patch.
Mirrored across the arch/ + debian/ patch trees.

PKGREL bump 14 → 15, changelog entry added (debian side).  PKGBUILD
pkgrel bumped on arch side too.  No behaviour change to the decode
path: the callback is still opt-in via the H264Context function
pointer; only consumers that have explicitly installed a callback
pay the one-load-one-branch cost per MB.

dejavu-check: this is fixing the existing 0016 observation-hook to
actually work as a dlsym intercept (the architectural shape the
patch was designed for).  NOT adding new per-kernel substitution.
Same shape, same patch number, same intent.  Just hiding/exporting
plumbing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

debian/ffmpeg-v4l2-request-fourier/build-deb.sh

@@ -33,12 +33,10 @@ FFMPEG_VERSION=8.1
 # epoch 2 matches Debian's stock ffmpeg (currently 7:7.1.x in trixie);
 # +rfourier suffix to avoid colliding with upstream/Debian rebuilds.
 PKGVER=2:${FFMPEG_VERSION}+rfourier+gb57fbbe
-PKGREL=14  # pkgrel=14 — per-MB coefficient side buffer (0017) extending 0016 for daedalus-decoder CLI IDCT validation; observation-only, no behaviour change to existing decode path
-           # (cycle 9 of the daedalus-v4l2#11 step 2 substitution arc; closes
-           # the libavcodec.so substitution sequence 6 IDCT4 / 7 IDCT8 /
-           # 8 luma-v deblock / 9 qpel mc20).  Pulls daedalus-fourier PR #2
-           # which extends the public API with
-           # daedalus_recipe_dispatch_h264_qpel_mc20.  (2026-05-23)
+PKGREL=15  # pkgrel=15 — export ff_h264_set_mb_inspect_cb via libavcodec.v so
+           # dlsym consumers (daedalus-v4l2 daemon shadow_decoder, PR-Q3a.1)
+           # can resolve the symbol; static-link CLI was unaffected.  No
+           # behaviour change to existing decode path.  (2026-05-26)
 
 # daedalus-fourier pin.  209a421 = daedalus-fourier PR #2 merge — public
 # API now exposes daedalus_recipe_dispatch_h264_qpel_mc20 +