feat: pi-devbox parity — typst PDF, terminal terminfo, nvim colour, host-ssh check, hygiene

Ports the base additions from pi-devbox v1.4.0 + v1.5.0 that opencode-devbox
lacked (opencode-devbox already tracks pi-devbox for CLI-toolset parity, v2.6.0):

- typst PDF engine for pandoc (v1.4.0) + the pandoc typst-template default-font
  patch (v1.5.0) so 'pandoc --pdf-engine=typst' works without -V mainfont.
  pandoc shipped since v2.6.0 as a front-end only (no PDF back-end). +xz-utils.
  Tracks latest; --build-arg TYPST_VERSION escape hatch.
- Terminal support (v1.5.0): ncurses-term + kitty-terminfo + a compiled
  xterm-ghostty alias (tic -x, use=ghostty), so wezterm/alacritty/foot/ghostty/
  kitty resolve TERM over SSH instead of degrading to a dumb fallback.
- Readable Neovim colours (v1.5.0): system-wide /etc/xdg/nvim/sysinit.vim with
  termguicolors.
- Host SSH reachability check at shell startup (v1.4.0): one-time probe in
  .bash_aliases warning (with fix steps + inline pubkey) when the Mac host is
  unreachable. The rest of the LAN stack was already present.
- .claude/settings.local.json added to the gitignore_global seed (v1.5.0).
- Repo hygiene (v1.5.0): LICENSE (MIT), THIRD_PARTY.md, hadolint CI job (pinned
  v2.14.0) + .hadolint.yaml, IDEAS.md backlog.

Base-affecting (Dockerfile.base + rootfs) → base-<hash> advances, base rebuilds.
smoke-test gains typst/PDF, terminfo, and nvim-tgc assertions. Validated:
hadolint clean on both Dockerfiles, bash -n OK, base-hash guard OK, workflow
guard OK. CHANGELOG v2.7.0.

Dockerfile.base

@@ -15,7 +15,7 @@
 # content-addressed over this file, so any byte change invalidates the
 # cache. Recommended cadence: once per release for security updates.
 #
-# BASE_REBUILD_DATE: 2026-05-14 (v1.14.50b — fresh apt + first promote-base-latest)
+# BASE_REBUILD_DATE: 2026-07-13 (v2.7.0 — typst PDF engine + terminal terminfo (ncurses-term/kitty/xterm-ghostty) + nvim true-colour; pi-devbox parity)
 #
 # See the project README's "Build pipeline" section for the rationale.
 
@@ -74,7 +74,10 @@ RUN apt-get update && \
     python3-venv \
     nano \
     pandoc \
+    xz-utils \
     graphviz \
+    kitty-terminfo \
+    ncurses-term \
     && ln -s /usr/bin/fdfind /usr/local/bin/fd \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*
@@ -314,6 +317,40 @@ RUN ARCH=$(case "${TARGETARCH}" in amd64) echo "x86_64" ;; arm64) echo "aarch64"
     chmod +x /usr/local/bin/tldr && \
     tldr --version
 
+# ── typst — lightweight PDF engine for pandoc (Markdown→PDF) ─────────
+# pandoc (apt-installed above) is only a front-end; rendering PDF needs a
+# back-end engine. Rather than a ~600 MB TeX Live install, we ship typst:
+# a single ~30 MB static Rust binary with no LaTeX dependency, used via
+# `pandoc --pdf-engine=typst`. A fuller TeX Live remains the higher-fidelity
+# fallback for anyone who needs LaTeX-exact output (install on demand).
+# Ported from pi-devbox (its v1.4.0 + v1.5.0 font-default fix).
+#
+# Follows the `latest` GitHub-release convention (like tealdeer/uv/bat).
+# typst ships a `.tar.xz` asset (hence xz-utils in the apt layer above)
+# that extracts to typst-<arch>-unknown-linux-musl/typst. Pin a specific
+# tag with --build-arg TYPST_VERSION=vX.Y.Z.
+#
+# We also patch pandoc's bundled typst template
+# (/usr/share/pandoc/data/templates/template.typst): its conf() defaults the
+# document font to an empty tuple (`font: ()`), so a naked
+# `pandoc --pdf-engine=typst` fails with "font fallback list must not be empty"
+# unless the caller passes `-V mainfont=...`. We default it to Libertinus Serif
+# (typst's own bundled default font) so PDF export works out-of-the-box.
+ARG TYPST_VERSION=latest
+RUN ARCH=$(case "${TARGETARCH}" in amd64) echo "x86_64" ;; arm64) echo "aarch64" ;; *) echo "x86_64" ;; esac) && \
+    V="${TYPST_VERSION}" && \
+    if [ "$V" = "latest" ]; then \
+      V=$(curl -sI --retry 5 --retry-delay 5 --retry-all-errors "https://github.com/typst/typst/releases/latest" | awk 'tolower($1)=="location:" { sub(/\r$/,"",$2); n=split($2,a,"/"); print a[n] }'); \
+    fi && \
+    V="${V#v}" && [ -n "$V" ] && \
+    echo "Installing typst ${V}" && \
+    curl -fsSL --retry 5 --retry-delay 5 --retry-all-errors "https://github.com/typst/typst/releases/download/v${V}/typst-${ARCH}-unknown-linux-musl.tar.xz" | tar -xJ -C /tmp && \
+    install /tmp/typst-${ARCH}-unknown-linux-musl/typst /usr/local/bin/typst && \
+    rm -rf /tmp/typst-${ARCH}-unknown-linux-musl && \
+    typst --version && \
+    sed -i 's/^  font: (),$/  font: ("Libertinus Serif",),/' /usr/share/pandoc/data/templates/template.typst && \
+    grep -q 'font: ("Libertinus Serif",),' /usr/share/pandoc/data/templates/template.typst
+
 # ── MemPalace — local-first AI memory system ─────────────────────────
 # Provides semantic search over conversation history via 29 MCP tools.
 # Always installed in the base (variant-independent). Set
@@ -494,6 +531,23 @@ COPY rootfs/home/developer/.bash_aliases     /etc/skel-devbox/.bash_aliases
 COPY rootfs/home/developer/.inputrc          /etc/skel-devbox/.inputrc
 COPY rootfs/home/developer/.gitignore_global /etc/skel-devbox/.gitignore_global
 
+# ── Editor defaults: system-wide Neovim true-colour ──────────────────
+# /etc/xdg/nvim/sysinit.vim is Neovim's system vimrc: it loads for every user
+# (before any personal ~/.config/nvim) and can still be overridden per-user.
+# Enables termguicolors so the default theme renders in 24-bit colour instead
+# of a muddy 256-colour fallback. Pairs with kitty-terminfo (installed above).
+COPY rootfs/etc/xdg/nvim/sysinit.vim /etc/xdg/nvim/sysinit.vim
+
+# ── Terminal support: xterm-ghostty terminfo alias ──────────────────
+# ncurses-term (installed above) covers wezterm/alacritty/foot/st and the base
+# `ghostty` entry, but Ghostty connects with TERM=xterm-ghostty, for which no
+# distro packages an entry. Ship a thin alias (use=ghostty) and compile it into
+# the system terminfo db with `tic -x`, so it inherits the maintained ghostty
+# capability set. The `infocmp` check fails the build if the entry didn't land.
+COPY rootfs/usr/local/share/terminfo-src/ghostty.terminfo /usr/local/share/terminfo-src/ghostty.terminfo
+RUN tic -x -o /usr/share/terminfo /usr/local/share/terminfo-src/ghostty.terminfo && \
+    infocmp -x xterm-ghostty >/dev/null
+
 # ── Entrypoint ────────────────────────────────────────────────────────
 COPY rootfs/usr/local/lib/opencode-devbox/ /usr/local/lib/opencode-devbox/
 COPY rootfs/usr/local/bin/dot-watch /usr/local/bin/dot-watch