docs: note host SSH startup check in CHANGELOG Unreleased

CHANGELOG.md

@@ -15,6 +15,16 @@ Pre-v1.0.0 tags followed the pi npm version (`v{pi_version}[letter]`).
 
 ### Added
 
+- **Host SSH reachability check at shell startup.** `~/.bash_aliases` (baked
+  into the image) now runs a one-time SSH probe on the first bash session of
+  each container. If the Mac host is not reachable (Remote Login disabled or
+  the `devbox_jump` key not yet authorized) it prints a clear warning with the
+  exact two steps to fix it, including the container's public key inline.
+  Subsequent shells in the same container skip the check (flag in `/tmp`,
+  cleared on recreate). Silent when SSH is working. Complements the existing
+  key-generation message in `setup-lan-access.sh` which only fires once at key
+  creation time and can easily be missed. Commit `4563b4d`.
+
 - **`typst` — lightweight PDF engine for pandoc (Markdown→PDF).** `pandoc` has
   shipped in the base since v1.0.0 but as a front-end only — with no PDF
   back-end installed, `studio_export_pdf` / `pandoc -o out.pdf` failed with