Add chroma cache to entrypoint chown loop, finalize v1.14.28b changelog

The ChromaDB embedding model cache at ~/.cache/chroma was missing
from the volume ownership-fix loop in entrypoint.sh. Without it,
the devbox-chroma-cache named volume would be root-owned on first
creation and mempalace search would fail with permission errors.

Update CHANGELOG.md from 'Unreleased' to v1.14.28b with the full
mempalace feature set (MCP auto-registration, two-volume split).

entrypoint.sh

@@ -81,6 +81,7 @@ for dir in \
   /home/"$USER_NAME"/.local/share/nvim \
   /home/"$USER_NAME"/.mempalace \
   /home/"$USER_NAME"/.cache/bash \
+  /home/"$USER_NAME"/.cache/chroma \
   /home/"$USER_NAME"/.rustup \
   /home/"$USER_NAME"/.cargo \
   /home/"$USER_NAME"/.vscode-server \