Fix what a review of the whole app found, end to end (0.67.1)

A pass over every feature against a real Docker daemon, then clicking
through the UI as admin and read-only user, on a desktop and a phone.

Security. /ws/deploy ran compose up for the read-only role; it is
admin-only now. A container's inspect view, a stack's compose file
(POSTGRES_PASSWORD: hunter2) and the viewer's .env tab no longer show
credentials to that role. Git branch and URL values that git would read
as options (-x, ext::) are refused. SFTP host keys are checked: pinned
on first use or entered by hand (key line or SHA256 fingerprint), a
different key is refused before the password is sent. A backup name
from the API can no longer reach outside the destination folder. The
file browser refuses to move or rename a browse root, as delete did.

Docker lifecycle. Closing the deploy console released the stack lock
while compose was still running and logged rc=None as success; deploys
and updates are now background runs that hold the lock to the end,
report the real exit code and can be re-attached to. Every closed log
view left a `compose logs -f` behind. A dozen open tabs exhausted the
default thread pool and hung the API; event and exec streams have their
own threads. Auto-update and the update endpoint ignored failed pulls.
A deleted git stack was recreated and started by the next webhook or
poll; deleting a stack now drops its git source, auto-update policy and
schedule entries. Deleting no longer walks into mounted shares, is
refused while a backup runs, and removes the containers even when the
compose file is broken. Stack folders compose has to normalise
(Nextcloud -> nextcloud) work everywhere and group correctly on the
volumes, networks and images pages.

Detection. Host port conflicts read the container's own network
namespace; /proc/1/net is read instead. Images referenced as docker.io/…
were never update-checked; local builds no longer report "needs
credentials". NVIDIA GPUs are read from the driver's procfs. The backup
dialog's "path mismatch" warning came from mountinfo's filesystem-relative
root and fired for any stacks folder on its own disk, ZFS dataset or
btrfs subvolume; the host path now comes from Docker's mounts.

Backups and destinations. The download ignored the folder/volume
selection (axios sent binds[]). Restoring under a new name kept the old
one. A report header past nginx's buffer turned a good backup into a
502. SFTP/S3 errors were bare 500s and "Test" did not try to write.
A destination used by a schedule could be deleted. Backup file names
are in the schedule's or the browser's time zone instead of UTC.

Editor and converter. `docker run` conversion produced invalid compose
for --network host, named volumes and -dit; --gpus and --mount were
dropped; a multi-line command pasted into the one-line field became
`image: ' '` (now a textarea, and flattened continuations are read).
Validation failed for env_file stacks. The editor overwrote unsaved
edits on every container event, lost them on a stray click (now asks),
threw when closing the diff, and its helper panel listed the starter
service "app" for every existing stack. Monaco is bundled instead of
loaded from jsdelivr, so the editor works offline (and monaco-editor
0.57 drops the dompurify advisory; axios and react-router updated).

UI. All times were two hours off: offset-less UTC from SQLite was read
as local time, and "next run" always said "just now". A token refresh
mid-session duplicated deploys, reset terminals and doubled logs. A
backend restart (update, self-update) signed everyone out on reload; the
page now waits for it. The editor was unusable on a phone, tables and
tabs overflowed, dialog text was black on the dark theme, and the file
browser opened on an error with the default roots. Read-only users get
"Admin only" pages instead of 403s; in-use networks offer no delete;
"Scan all" covers StackPilot's own stacks only and runs in the
background instead of timing out at 600s.

Deployment. nginx passes the port in Host (the OIDC redirect URI lost
:5009) and keeps an outer proxy's X-Forwarded-Proto. The frontend waits
for a healthy backend (healthcheck probes every 2s while starting). The
frontend image builds with npm ci. Secrets are 0644 in a 0700 folder so
non-root containers can read them; existing files are fixed at startup.
The test suite no longer starts real containers on a host with Docker.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Fx7gcuy8d6nPd95g43rGHu

README.md

@@ -652,6 +652,13 @@ it is what your saved destination credentials are encrypted with.
   `local_lock=` yourself: with locking the kernel needs rpcbind on the Docker
   host (nfs-common), and without it the mount fails with "connection refused".
   Only StackPilot writes the backup files, so nothing needs locking (0.66.2).
+- **SFTP host keys** (0.67.1): the server's host key is checked on every
+  connection. Paste it into the destination's *Host key* field (a key line or
+  its `SHA256:` fingerprint, e.g. from `ssh-keyscan HOST | ssh-keygen -lf -`),
+  or leave the field empty and the key seen on the first connection is pinned
+  — "Test" shows its fingerprint. A different key is refused before the
+  password is sent; clear the field after a server reinstall to trust the new
+  one. Changing the host or port forgets the pinned key.
 - **Push & restore**: the stack Backup dialog can push straight to a destination
   instead of downloading; the Restore dialog can browse a destination's backups
   and restore (volumes included) directly from it. Backups can also be
@@ -665,7 +672,9 @@ it is what your saved destination credentials are encrypted with.
 - **Local time** (0.66.0): each schedule has a time zone, preset to the
   browser's (e.g. `Europe/Berlin`), and its time is wall-clock time there — a
   03:00 backup stays at 03:00 across daylight saving changes. Schedules made
-  before were in UTC and stay so until edited.
+  before were in UTC and stay so until edited. Backup file names carry the time
+  on that clock too (`backup-app-full-20261015-122154.tar.gz` for 12:21:54 in
+  Berlin); a backup made by hand uses the browser's time zone (0.67.1).
 - **Several stacks per schedule** (0.65.0): tick any number of stacks, or
   *All stacks* to include stacks added later without editing the schedule. They
   are backed up one after another, each to its own file with its own retention