docs: the 0.1.0 notes carry #39/#41 — the getent-$HOME installer fix shipped without its entry

Both reviewers caught it: #41 merged after the changelog convention
landed (#40) and skipped its entry; the release PR is the last gate
before the section becomes the permanent release body.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -20,6 +20,16 @@ on the way to cutting its first release, and this file starts there.
   and right after one — the exact `changelog_section` the workflow runs
   extracts it non-empty. The rotting issue-number grep is gone.
 
+- **The installer survives an environment with no `$HOME`** (#39) —
+  cloud-init's `runcmd` runs `install.sh` with no `$HOME` set, and under
+  `set -u` the first expansion died with a bash unbound-variable stack
+  instead of an install — found live by box#88's template seed, which
+  pins `HOME=/root` as its own scar. The installer now derives the home
+  from `getent` for the effective user (root included) before any path
+  is built from `$HOME`, and when getent has no answer either it refuses
+  by name. Driven with a shim getent both ways: the derived-home install
+  lands, the no-answer refusal is pinned. (#41 — merged without its
+  entry; restored here at the release gate.)
 - **Headless credential prompts refuse loudly instead of dying silently**
   (#42) — the interactive credential prompts (`TS_AUTHKEY` in `bootstrap`,
   `RUNNER_TOKEN` in `runner install`, `RUNNER_REMOVE_TOKEN` in