release: audited bumps (pi 0.85.1, mempalace 3.9.0, atelier v0.10.1) + two guards

Version audit for the next release. pi 0.84.4 -> 0.85.1, deliberately skipping
0.85.0 (it published internal experimental code and broke SDK imports,
upstream #9132). mempalace 3.8.0 -> 3.9.0. pi-atelier v0.10.0 -> v0.10.1.
PI_STUDIO_VERSION relabelled none -> v0.9.60-rc.0 so the floating main ref's
RC status is visible at docker-inspect time instead of discovered later.
PI_FORK_REF stays floating and adopts e69725c.

The pi bump was verified by running it under a pty in five combinations rather
than by reading the changelog, because this repo has already shipped a version
pair no changelog flagged (atelier < 0.7.1 hangs pi >= 0.84). CPU delta
0.00-0.01s over 5s against a ~5s sustained-CPU hang signature, two-sided via
the atelier sidebar painting identically to the 0.84.4 control.

NODE_VERSION stays 22 on purpose: node 24 is technically safe (pi's five
prebuilt addons are all NAPI, nothing declares a ceiling, agent-browser's
engines.node >=24 is vestigial for the shipped aarch64 ELF), but this release
already moves two minors and bakes an RC, and a node major would leave four
suspects if the image misbehaves. Own release, smoke suite as the gate.

Also corrects a stale claim at the mempalace ARG: synlig serves 3.8.0
server-side, not 3.7.1 (measured over ssh 2026-09-06).

agent-browser volume shadowing: the image has shipped 0.35.2, but every
session on mbp-m1-2020 ran 0.27.0 from a 2026-07-17 hand-install in
~/.pi/npm-global (a VOLUME, at PATH position 2 vs /usr/bin at 8). Third
package hit by this hazard after pi and pi-atelier, so the guard is now
generalised: entrypoint-user.sh retires the copy by moving it aside
(reversible, only when the image ships its own), recreate-sanity-check.sh
asserts resolution under /usr where the volume is real, smoke-test.sh carries
the build-time half and says in the source why it is weak. The real damage was
the stale BUNDLED SKILL (3 skillsets/17.6 KB vs 8/31.5 KB, ten subcommands
undocumented to the agent) - a stale tool errors, a stale skill quietly
teaches wrong commands.

pi-fork capability floor (extensions: []): forks were measured across four
dispatches ignoring their brief, answering in the user's voice, fabricating
self-referential measurements, and once filing a diary entry as agent_name=pi.
Cause is upstream by design - the child gets getHeader()+getBranch(), the
whole active session branch, with the brief as the final user message. Not a
model-capability problem: the same model as the fast profile obeyed the
identical brief perfectly with a fresh session and no inherited context.
extensions: [] runs children with --no-extensions, so the mempalace bridge is
absent and palace writes are impossible by construction (verified by asking a
child to enumerate its tools: read, bash, edit, write). Removes palace writes,
not filesystem writes.

scripts/smoke-test.sh

@@ -718,6 +718,34 @@ exec_test "pi-atelier registered in packages[] (TUI sidebar)" \
 exec_test "pi-atelier registered from /opt, not npm: (volume-shadowing guard)" \
   'jq -e "((.packages // []) | any((type == \"string\") and endswith(\"/pi-atelier\"))) and (((.packages // []) | any(. == \"npm:pi-atelier\")) | not)" $HOME/.pi/agent/settings.json'
 
+# agent-browser: the third package hit by ~/.pi/npm-global volume shadowing
+# (after pi itself and pi-atelier). This build-time check is deliberately WEAK
+# and says so: a `docker run` container has an EMPTY config volume, so it can
+# only prove the image ships a sane copy and nothing in the image itself
+# shadows it. The check that actually bites lives in
+# recreate-sanity-check.sh, which runs where the volume is real — that is
+# where a 7-week-old 0.27.0 was caught shadowing 0.35.2 on 2026-09-06.
+exec_test "agent-browser resolves under /usr (volume-shadowing guard, build-time half)" '
+  p=$(command -v agent-browser) || { echo "agent-browser not on PATH" >&2; exit 1; }
+  r=$(readlink -f "$p")
+  echo "resolved=[$r] version=[$(agent-browser --version 2>/dev/null | head -n1)]" >&2
+  case "$r" in /usr/*) ;; *) exit 1 ;; esac
+  test ! -d "$HOME/.pi/npm-global/lib/node_modules/agent-browser" || exit 1
+  echo ok
+'
+
+# pi-fork capability floor. `extensions: []` makes a fork child run with
+# --no-extensions, which is the only MECHANICAL guarantee that a fork cannot
+# file drawers or diary entries under the parent's identity — the mempalace
+# bridge is an extension, so removing extensions removes the write path.
+# Asserted because it is a security-shaped default that a settings merge or a
+# hand-edit could silently drop, and its absence is invisible until a fork
+# writes to the shared palace as you (measured twice: 2026-09-01, 2026-09-06).
+# Deliberately compares to [] and not "is falsy": null means "load normal
+# extensions", i.e. exactly the unguarded state this asserts against.
+exec_test "pi-fork extensions floor is [] (forks cannot write to the palace)" \
+  'jq -e ".[\"pi-fork\"].extensions == []" $HOME/.pi/agent/settings.json'
+
 # ── /tmp/sshcm directory created by entrypoint ────────────────────────
 exec_test "/tmp/sshcm dir mode 700 (ssh ControlMaster)" \
   'test -d /tmp/sshcm && [ "$(stat -c %a /tmp/sshcm)" = "700" ] && echo ok'