Render emoji with a Chrome-PDF-compatible Twemoji build

The previous attempt (8171669, reverted in 8abef81) installed upstream
Twemoji's own release, which uses the SVGinOT color-font format. Chrome
renders SVGinOT in color on screen, but its print-to-PDF path doesn't
support it and silently falls back to the font's monochrome outline
glyphs -- confirmed via `pdffonts` showing the embedded glyphs as a
plain (non-color) font subset in a real CI-built poster.

Fedora's twitter-twemoji-fonts package instead ships Twemoji as
CBDT/CBLC (bitmap glyphs), the same technology Noto Color Emoji uses,
which Chrome does support for PDF export (verified locally: embeds as
a color Type 3 font, and renders correctly in the printed poster).
Extract just the .ttf from Fedora's RPM via rpm2cpio/cpio rather than
adding a whole extra package repository.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Change-Id: Ic6168efa44af3b0a84ecdb643e483d107aaac547
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d47a714..2599805 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -169,8 +169,14 @@
 
     - start_section install_fonts "Installing Fira, Twemoji and emoji fonts"
     - curl -Ls https://github.com/mozilla/Fira/archive/refs/tags/4.202.tar.gz | tar -C /usr/share/fonts -zx --wildcards "*.otf"
-    - curl -Ls https://github.com/13rac1/twemoji-color-font/releases/download/v15.1.0/TwitterColorEmoji-SVGinOT-Linux-15.1.0.tar.gz | tar -C /usr/share/fonts -zx --wildcards "*.ttf"
-    - apt-get install --no-install-recommends -o dir::cache::archives="$APT_CACHE_DIR" -y fonts-noto-color-emoji fonts-symbola
+    - apt-get install --no-install-recommends -o dir::cache::archives="$APT_CACHE_DIR" -y rpm2cpio cpio fonts-noto-color-emoji fonts-symbola
+    # Fedora's twitter-twemoji-fonts package ships a CBDT/CBLC (bitmap) build
+    # of Twemoji. Use that rather than upstream's own SVGinOT release: Chrome
+    # renders SVGinOT in color on screen, but its print-to-PDF path silently
+    # falls back to the font's monochrome outline glyphs for that format --
+    # CBDT/CBLC (like Noto Color Emoji) embeds correctly as a color PDF font.
+    - curl -sLo /tmp/twemoji.rpm https://dl.fedoraproject.org/pub/fedora/linux/releases/44/Everything/x86_64/os/Packages/t/twitter-twemoji-fonts-14.0.2-10.fc44.noarch.rpm
+    - (cd / && rpm2cpio /tmp/twemoji.rpm | cpio -idm ./usr/share/fonts/twemoji/Twemoji.ttf)
     - fc-cache
     - end_section install_fonts
 
diff --git a/inst/rmarkdown/templates/posterdown_ids/resources/template.html b/inst/rmarkdown/templates/posterdown_ids/resources/template.html
index 45cdf20..255d382 100644
--- a/inst/rmarkdown/templates/posterdown_ids/resources/template.html
+++ b/inst/rmarkdown/templates/posterdown_ids/resources/template.html
@@ -60,7 +60,7 @@
 padding: 0;
 padding-bottom: 2.54cm;
 text-align: justify;
-font-family: $if(font_family)$$font_family$$else$Fira Sans$endif$, "Twitter Color Emoji", Twemoji, "Noto Color Emoji", "Segoe UI Emoji";
+font-family: $if(font_family)$$font_family$$else$Fira Sans$endif$, Twemoji, "Noto Color Emoji", "Segoe UI Emoji";
 hyphens: auto;
 background: white;
 }