firefox-fourier: flatten patches to top-level (makepkg has no subdir support)

Follow-up to #10. The subdir layout I assumed worked turned out to not
work — per 'man PKGBUILD':

  The filename in the array must NOT include any path components like ./

makepkg's source-staging only honors basenames; the patches/ subdir
references staged the files but the basename-lookup at apply time
failed with the same 'not found in build directory' error that #9 hit.

I copied the chromium-fourier convention thinking it was proven, but
chromium-fourier has no CI either and likely has the same latent
breakage (separate issue, not in this PR's scope).

The actually-working pattern is the mpv-fourier one: patches at the
top level next to the PKGBUILD. mpv-fourier iter2 just built green
on CI (#92) with that layout.

This commit:
- Moves all 8 patches (5 fourier + 3 arch upstream) from patches/
  to arch/firefox-fourier/ via git mv (preserves blame).
- Removes the now-empty patches/ subdir.
- Strips 'patches/' prefix from source array entries.
- Strips '/patches' from prepare() patch -i paths.

No semantic change to the patch content or apply order.

pkgrel 3 -> 4.

arch/firefox-fourier/PKGBUILD

@@ -13,7 +13,7 @@
 
 pkgname=firefox-fourier
 pkgver=150.0.1
-pkgrel=3
+pkgrel=4
 pkgdesc='Firefox with V4L2 stateless HW video decode unlocked for mainline Linux Rockchip'
 arch=('aarch64' 'x86_64')
 url='https://www.mozilla.org/firefox'
@@ -79,15 +79,15 @@ source=(
   # walls. arch-0001 (install-under-remoting) skipped — our launcher
   # ships under /usr/bin/firefox-fourier with our own wrapper.
   # https://gitlab.archlinux.org/archlinux/packaging/packages/firefox
-  'patches/arch-0002-Bug-2033279-Make-enable-rust-simd-work-with-Rust-1.9.patch'
-  'patches/arch-0003-Patch-glsl-optimizer-to-build-with-glibc-2.43.patch'
-  'patches/arch-0004-Bug-2023597-Use-wasm32-wasip1-target-for-clang-22.1-.patch'
+  'arch-0002-Bug-2033279-Make-enable-rust-simd-work-with-Rust-1.9.patch'
+  'arch-0003-Patch-glsl-optimizer-to-build-with-glibc-2.43.patch'
+  'arch-0004-Bug-2023597-Use-wasm32-wasip1-target-for-clang-22.1-.patch'
   # firefox-fourier patches — V4L2 stateless decode unlock.
-  'patches/0001-gfxinfo-v4l2-stateless-fourccs.patch'
-  'patches/0002-libwrapper-hwdevice-ctx-create.patch'
-  'patches/0003-ffmpegvideo-v4l2-request-route.patch'
-  'patches/0004-prefs-v4l2-request.patch'
-  'patches/0005-rdd-sandbox-v4l2-media-ctl.patch'
+  '0001-gfxinfo-v4l2-stateless-fourccs.patch'
+  '0002-libwrapper-hwdevice-ctx-create.patch'
+  '0003-ffmpegvideo-v4l2-request-route.patch'
+  '0004-prefs-v4l2-request.patch'
+  '0005-rdd-sandbox-v4l2-media-ctl.patch'
   # Vendor-default prefs that gate the patched VAAPI path on RK3399 —
   # widget.dmabuf.force-enabled etc. See marfrit-packages#8 for evidence.
   'rockchip-fourier-defaults.js'
@@ -98,16 +98,16 @@ prepare() {
   cd "${srcdir}/firefox-${pkgver}"
 
   # Toolchain glue (Arch upstream) — apply BEFORE the fourier patches.
-  patch -Np1 -i "${srcdir}/patches/arch-0002-Bug-2033279-Make-enable-rust-simd-work-with-Rust-1.9.patch"
-  patch -Np1 -i "${srcdir}/patches/arch-0003-Patch-glsl-optimizer-to-build-with-glibc-2.43.patch"
-  patch -Np1 -i "${srcdir}/patches/arch-0004-Bug-2023597-Use-wasm32-wasip1-target-for-clang-22.1-.patch"
+  patch -Np1 -i "${srcdir}/arch-0002-Bug-2033279-Make-enable-rust-simd-work-with-Rust-1.9.patch"
+  patch -Np1 -i "${srcdir}/arch-0003-Patch-glsl-optimizer-to-build-with-glibc-2.43.patch"
+  patch -Np1 -i "${srcdir}/arch-0004-Bug-2023597-Use-wasm32-wasip1-target-for-clang-22.1-.patch"
 
   # Fourier patches — order matters; see ../PLAN.md for rationale.
-  patch -Np1 -i "${srcdir}/patches/0001-gfxinfo-v4l2-stateless-fourccs.patch"
-  patch -Np1 -i "${srcdir}/patches/0002-libwrapper-hwdevice-ctx-create.patch"
-  patch -Np1 -i "${srcdir}/patches/0003-ffmpegvideo-v4l2-request-route.patch"
-  patch -Np1 -i "${srcdir}/patches/0004-prefs-v4l2-request.patch"
-  patch -Np1 -i "${srcdir}/patches/0005-rdd-sandbox-v4l2-media-ctl.patch"
+  patch -Np1 -i "${srcdir}/0001-gfxinfo-v4l2-stateless-fourccs.patch"
+  patch -Np1 -i "${srcdir}/0002-libwrapper-hwdevice-ctx-create.patch"
+  patch -Np1 -i "${srcdir}/0003-ffmpegvideo-v4l2-request-route.patch"
+  patch -Np1 -i "${srcdir}/0004-prefs-v4l2-request.patch"
+  patch -Np1 -i "${srcdir}/0005-rdd-sandbox-v4l2-media-ctl.patch"
 
   cp "${srcdir}/mozconfig" .mozconfig
 }