release: v1.4.0 — typst PDF engine + host SSH startup check

Finalize the Unreleased batch as v1.4.0 (minor — significant base
additions). Base rebuilds (Dockerfile.base for typst/xz-utils;
.bash_aliases for the SSH check). pi auto-resolves latest (0.80.3 ->
0.80.6); mempalace stays 3.5.0 (current).

CHANGELOG.md

@@ -11,7 +11,16 @@ Pre-v1.0.0 tags followed the pi npm version (`v{pi_version}[letter]`).
 
 ---
 
-## Unreleased
+## v1.4.0 — 2026-07-11
+
+Minor release. Headline: **PDF export works out of the box** — the base now
+ships **`typst`** as the pandoc PDF engine (`pandoc --pdf-engine=typst`), so
+`studio_export_pdf` / `pandoc -o out.pdf` no longer fail with "xelatex not
+found". Also adds a **host SSH reachability check at shell startup**. Both are
+base-affecting (`Dockerfile.base` apt+RUN for typst/xz-utils; `.bash_aliases`
+for the SSH check is COPYd into the base), so the base rebuilds and both land in
+`base-<hash>`. pi auto-resolves `latest` at build time (0.80.3 → 0.80.6);
+mempalace stays pinned at 3.5.0 (current PyPI latest).
 
 ### Added