v0.66.1: inject USERDATA_PATH on first deploy too (shared withUserdataPath)

DeployStack's initial compose-up builds env from deploy values (not stackEnv), so
v0.66.0 missed USERDATA_PATH on first deploy → ${USERDATA_PATH} resolved to '' and
Docker bound a root-owned dir at the container root (found live: radarr /media/movies
was 0:0 755). Shared withUserdataPath injector now used by stackEnv AND
composeExecWithEnv. Regression test included.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,15 @@
 ## Changelog
 
+### v0.66.1 — fix USERDATA_PATH on first deploy (2026-06-14)
+
+The initial deploy path (`DeployStack` → `composeExecWithEnv`) builds its compose env from the deploy
+values, not from app.yaml via `stackEnv` — so v0.66.0 injected `USERDATA_PATH` only on start/redeploy,
+NOT on the FIRST deploy. A freshly-deployed app resolved `${USERDATA_PATH}` to `""` and Docker bound a
+bogus root-owned dir at the container root (e.g. `/media/movies`) instead of `<drive>/userdata/...`
+(found live: radarr's media mount was `0:0 755` at the container root). Fix: a shared `withUserdataPath`
+injector used by BOTH `stackEnv` and `composeExecWithEnv`. Regression test asserts injection on/off by
+HDD_PATH presence.
+
 ### v0.66.0 — userdata layout + shared-storage ownership convention (2026-06-14)
 
 Customer-facing `userdata/` tree (sibling of appdata/backups under each drive's felhom-data namespace)