Web UI: install/reconfigure addons, default-on install, visual redesign (v2.17.0)

Web UI now installs by default during first-time provisioning (fixed
port 8090, no prompt) instead of being opt-in, and can install/
reconfigure CUPS Printing, LMS Server, Squeezelite Player, and Asterisk
Intercom, and check for updates - the addons and Update action asked
for by name.

Privilege model: the web service itself still runs as $KIOSK_USER with
zero ambient sudo. A new narrow, allow-listed root helper
(menus/addon_webui.sh's webui_write_helper_script) is the only way it
ever gains privilege, reachable only via a single-path passwordless
sudo rule generated and validated with `visudo -c -f` before being
installed, and it re-checks its own fixed action allow-list before
dispatching anything. Each allow-listed action is the exact same
interactive action_* function the terminal menu already uses, driven
by piping the right answers on stdin - the same technique this
project's own bash tests already use, so no prompt/mutation refactor
of any addon file was needed. webui/lib/actions.js's stdin sequences
were cross-validated against the real bash functions (not just read),
which caught two real bugs (Squeezelite and Asterisk Intercom both
silently lost their "decline reconfigure" path).

Long-running installs stream live output via Server-Sent Events
(webui/lib/jobs.js), one action at a time.

Full visual redesign: a sidebar shell (Sites/Display/Lockout/Addons/
Update) replacing the single scrolling page, light+dark themes via
prefers-color-scheme, no external font/CDN dependency. Actually driving
the redesigned UI in a headless browser (not just reading the code)
caught a real bug: refreshing an addon's pill/button after a successful
install used to rebuild the whole card, racing (and usually losing to)
the success status/log that job had just written. Fixed to update
pill/buttons in place.

Uninstall-via-web is deliberately still not offered, for any addon.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VfsFSoRqfbRG7XAg5RoE7e

Readme.md

@@ -1,6 +1,6 @@
 # Ubuntu Based Kiosk
 
-**Current Version:** 2.16.0 (check script header for latest version)
+**Current Version:** 2.17.0 (check script header for latest version)
 **Built with Claude Sonnet 4.6 AI assistance**
 **License:** GPL v3 - Keep derivatives open source
 **Repository:** https://github.com/outis1one/ubuntu-based-kiosk/
@@ -1291,13 +1291,17 @@ terminal menu and the web UI, so they can't drift apart).
   steps, so any code or hardware-config change picked up by the pull
   actually takes effect. Also offers an on-demand Electron version
   check. See "Recent Updates (v2.15.0)" below.
-- `webui/` + `menus/addon_webui.sh` — **Web UI** (Addons): a small
-  Node/Express app installed as a systemd service under `$KIOSK_USER`,
-  giving a browser-based editor for Sites & Page Timing, Display &
-  Interaction, and Password Protection & Lockout — no login of its own,
-  put it behind your own reverse proxy with Authelia forward-auth if
-  it needs to be reachable beyond a trusted LAN. See "Recent Updates
-  (v2.16.0)" below.
+- `webui/` + `menus/addon_webui.sh` — **Web UI** (Addons, installed by
+  default during provisioning): a small Node/Express app running as a
+  systemd service under `$KIOSK_USER` with zero ambient `sudo`, giving
+  a browser-based editor for Sites & Page Timing, Display & Interaction,
+  and Password Protection & Lockout, plus install/reconfigure for CUPS,
+  LMS/Squeezelite, and Asterisk Intercom, and Update — each reached
+  through a narrow, allow-listed root helper
+  (`webui_write_helper_script`) rather than any ambient privilege on
+  the service itself. No login of its own, put it behind your own
+  reverse proxy with Authelia forward-auth if it needs to be reachable
+  beyond a trusted LAN. See "Recent Updates (v2.17.0)" below.
 - `install.sh` — entry point for the modular tool, now grouped **Core
   Settings / Addons / Advanced** like the legacy menu. On a machine
   with no kiosk installed yet, it provisions one first (see
@@ -1353,9 +1357,18 @@ full migration pass.
 
 ## Project Status & Future Plans
 
-**Current Version:** 2.16.0
+**Current Version:** 2.17.0
 
-**Recent Updates (v2.16.0):**
+**Recent Updates (v2.17.0):**
+- **Web UI now installs by default** during first-time provisioning (fixed port 8090, no prompt) instead of being opt-in — the Addons menu entry still works standalone for reconfiguring the port or reinstalling it on a kiosk provisioned before this change.
+- **The web UI can now install/reconfigure CUPS Printing, LMS Server, Squeezelite Player, and Asterisk Intercom, and check for updates** — the same four addons plus Update named directly. Every one of these is the exact same interactive `action_*` function the terminal menu already uses (no prompt/mutation refactor of any addon file), driven by piping the right answers on stdin — the same technique this project's own bash tests already use to drive these functions.
+- **Privilege model:** the web service itself still runs as `$KIOSK_USER` with zero ambient `sudo`. A new narrow, allow-listed root helper is the only way it ever gains privilege — reachable only via a single-path passwordless sudo rule (generated and validated with `visudo -c -f` before being installed), and it re-checks its own fixed action allow-list before dispatching anything. Chosen over running the whole service as root after asking directly: since this repo has no login of its own by design, a request that reaches the web UI with no reverse proxy in front is effectively unauthenticated, so the allow-list bounds what that can actually do to five vetted actions, never a root shell.
+- Long-running installs stream live output to the browser via Server-Sent Events, one action at a time — a second request while one is in flight gets a clear `409`, never silently queued or dropped.
+- **Full visual redesign:** a sidebar shell (Sites/Display/Lockout/Addons/Update) replacing the single scrolling page of three cards, both light and dark themes via `prefers-color-scheme`, no external font/CDN dependency.
+- A real bug was found and fixed by actually driving the redesigned UI in a headless browser, not just by reading the code: refreshing an addon's pill/button after a successful install used to rebuild the whole card, which raced (and usually lost to) the success status/log that same job had just written a moment earlier. Fixed to update the pill/buttons in place, leaving the completed job's log exactly as the user left it.
+- Uninstall-via-web is deliberately still not offered, for any addon — flagged as needing its own double-confirmation design, not bundled into this pass. WiFi, Timezone, Power/Display/Quiet Hours, Diagnostics, Remote Access, Authelia, Factory Reset, Virtual Consoles, Emergency Hotspot, Clone Settings, and the fleet/multi-kiosk dashboard all remain out of scope for the web UI too — each a named, sequenced follow-up, not an oversight.
+
+**Previous (v2.16.0):**
 - **New: Web UI** (Addons → Web UI) — a small Node/Express app (`webui/`) giving a browser-based editor for Sites & Page Timing, Display & Interaction, and Password Protection & Lockout, the three Core Settings menus that are pure `config.json` read/write with no privileged system mutation involved. Runs as a systemd service under `$KIOSK_USER` (the same user Electron runs as), so it never needs `sudo` — it reads/writes `config.json` with normal filesystem permissions.
 - `webui/lib/config.js` re-implements `lib/config.sh`'s exact field list, defaults, and merge-on-save contract in JS — `kiosk-app/main.js` already reads the same `config.json` directly in JS, so this isn't a new pattern — meaning it can never silently clobber fields it doesn't track (Authelia's credentials, the unused quiet-hours fields, etc), the same failure mode previously fixed in `lib/config.sh`'s own history.
 - **No login of its own, by design.** Authelia runs elsewhere; the expectation is a reverse proxy (e.g. Caddy) with Authelia forward-auth in front of it, the same way other self-hosted apps get protected — Authelia integration is explicitly out of scope for this repo. Direct LAN access with no proxy in front has no authentication at all — treat it like SSH access to the kiosk.