kiosk: disable weak deps + add package-footprint audit

The kiosk dnf transaction was measured at 229 pkgs / 1.0 GB. Nearly all
of the non-core packages are Recommends: a locked-down single-URL kiosk
never uses flatpak + its ostree/bubblewrap sandbox runtime, tracker-miners
(a filesystem indexer — dead weight and a threat surface), the pipewire/
pulseaudio audio stack, or libproxy-webkitgtk4 -> webkit2gtk3-jsc (an 8.9M
second browser engine dragged into a Chromium kiosk for libproxy's PAC
runner).

Add --setopt=install_weak_deps=False to cut them, and an rpm -qa size
manifest to the build log so the next CI build reports the exact new
footprint (turning 'seems unnecessary' into data for the next trim round:
gstreamer/media codecs, or mesa-dri-drivers if the GPU path is abandoned).

The immovable floor is chromium + chromium-common + llvm-libs (mesa sw-GL)
+ gtk3/adwaita + libicu, all hard deps. BENCH-VERIFY the kiosk still
renders with weak deps off (watch for a missing font or libva).

diskless.pkr.hcl

@@ -459,7 +459,27 @@ build {
       # the heaviest items here and are likely unnecessary given weston
       # --use-pixman + chromium --disable-gpu — candidate to drop once the kiosk
       # is display-verified; see TODO #4.)
-      "dnf install -y --setopt=tsflags=nodocs weston chromium mesa-dri-drivers mesa-libEGL mesa-libgbm dejavu-sans-fonts",
+      #
+      # install_weak_deps=False: a locked-down single-URL kiosk needs none of the
+      # Recommends: this transaction otherwise drags in — flatpak + its ostree/
+      # bubblewrap sandbox runtime, tracker-miners (a filesystem indexer, both
+      # dead weight AND a threat surface), the pipewire/pulseaudio audio stack,
+      # and libproxy-webkitgtk4 → webkit2gtk3-jsc (a whole SECOND browser engine
+      # pulled into a Chromium kiosk just for libproxy's PAC runner). Measured:
+      # the default (weak-deps=on) transaction was 229 pkgs / 1.0 GB. The floor
+      # that survives is chromium + chromium-common + llvm-libs (mesa sw-GL) +
+      # gtk3/adwaita + libicu — all HARD deps. If a genuine runtime dep turns out
+      # to be a weak dep (e.g. a font, or libva for VA-API on the GPU path), add
+      # it to the explicit list below rather than re-enabling weak deps wholesale.
+      "dnf install -y --setopt=tsflags=nodocs --setopt=install_weak_deps=False weston chromium mesa-dri-drivers mesa-libEGL mesa-libgbm dejavu-sans-fonts",
+      # Footprint audit (surfaces in the CI build log): the installed set, largest
+      # first, + a total count. Turns 'seems unnecessary' into data for the next
+      # trim round (e.g. dropping gstreamer/media codecs if the SPA plays no HTML5
+      # media, or mesa-dri-drivers if the GPU path is abandoned). %%{...} is escaped
+      # for Packer's HCL2 template engine (a bare %%{ is parsed as a directive).
+      "echo '==> kiosk package footprint (installed size, largest 40 first):'",
+      "rpm -qa --qf '%%{SIZE}\\t%%{NAME}-%%{VERSION}-%%{RELEASE}\\n' | sort -rn | head -40",
+      "echo \"==> total packages installed after kiosk: $(rpm -qa | wc -l)\"",
       # Unprivileged, passwordless kiosk user. Groups: 'video' (KMS /dev/dri/card0
       # for weston) + 'input' (libinput) as a seat fallback; 'render'
       # (/dev/dri/renderD128) so Chromium's GPU process can do hardware raster on

docs/TODO.md

@@ -306,6 +306,19 @@ step 8 and §5). Retire/reset the errata afterward. Needs the design-doc source
 trim, ship via CI `enable_kiosk=true`) and the phone-home/NTP lockdown (done) —
 all captured in the sub-notes below. Secure-path render check is folded into #8.
 
+**Package-footprint trim (2026-07-03):** the kiosk dnf transaction was measured at
+**229 pkgs / 1.0 GB** (weak deps ON). Added `--setopt=install_weak_deps=False` to
+the install in `diskless.pkr.hcl` — drops the flatpak/ostree sandbox runtime,
+tracker-miners (fs indexer = dead weight + threat surface), the pipewire/pulseaudio
+audio stack, and `libproxy-webkitgtk4 → webkit2gtk3-jsc` (an 8.9M *second* browser
+engine). Also added an `rpm -qa --qf %%{SIZE}` size-manifest diagnostic to the build
+log to quantify the result. The immovable floor is chromium + chromium-common +
+llvm-libs (mesa sw-GL) + gtk3/adwaita + libicu — all HARD deps. **BENCH-VERIFY:**
+with weak deps off, confirm the kiosk still renders (no genuine runtime dep was a
+weak dep — watch for a missing font or `libva`). NEXT trim candidates (measure via
+the new manifest): gstreamer/media codecs if the SPA plays no HTML5 media;
+mesa-dri-drivers + `--use-pixman`-only if the GPU path is abandoned.
+
 
 **WORKING / display-verified 2026-06-17** (kiosk renders Chromium fullscreen on
 the configured URL). Build-flagged OFF by default for now (`enable_kiosk=false`)