feat(settings): server global brightness and Wi-Fi driver resync

- Serve GET /settings as JSON by removing duplicate HTML route (use /settings/page for the standalone UI).

- Save global_brightness via PUT; broadcast to connected drivers; push saved level when outbound WS connects.

- Zones UI loads brightness from GET /settings only (no localStorage).

- Bump led-driver submodule for settings.save on brightness with save flag.

- Extend API doc and endpoint tests for global_brightness.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/static/zones.js

@@ -2,32 +2,12 @@
 let currentZoneId = null;
 let brightnessSendTimeout = null;
 
-const UI_BRIGHTNESS_STORAGE_KEY = "led_controller_ui_brightness";
-
 function clamp255(n) {
     const v = parseInt(n, 10);
     if (Number.isNaN(v)) return null;
     return Math.max(0, Math.min(255, v));
 }
 
-function loadSavedUiBrightness() {
-    try {
-        const raw = localStorage.getItem(UI_BRIGHTNESS_STORAGE_KEY);
-        if (raw == null) return null;
-        return clamp255(raw);
-    } catch (_) {
-        return null;
-    }
-}
-
-function persistUiBrightness(value) {
-    const v = clamp255(value);
-    if (v === null) return;
-    try {
-        localStorage.setItem(UI_BRIGHTNESS_STORAGE_KEY, String(v));
-    } catch (_) {}
-}
-
 function applyBrightnessSliders(val) {
     const v = clamp255(val);
     if (v === null) return;
@@ -37,9 +17,25 @@ function applyBrightnessSliders(val) {
     if (menuSlider) menuSlider.value = String(v);
 }
 
+async function saveGlobalBrightnessToServer(val) {
+    try {
+        const res = await fetch("/settings/settings", {
+            method: "PUT",
+            headers: { "Content-Type": "application/json", Accept: "application/json" },
+            credentials: "same-origin",
+            body: JSON.stringify({ global_brightness: val }),
+        });
+        if (!res.ok) {
+            const err = await res.json().catch(() => ({}));
+            console.warn("global_brightness save failed:", err.error || res.status);
+        }
+    } catch (e) {
+        console.warn("global_brightness save failed:", e);
+    }
+}
+
 function sendZoneBrightness(value) {
     const val = Math.max(0, Math.min(255, parseInt(value, 10) || 0));
-    persistUiBrightness(val);
     const headerSlider = document.getElementById('header-brightness-slider');
     const menuSlider = document.getElementById('menu-brightness-slider');
     if (headerSlider && String(headerSlider.value) !== String(val)) {
@@ -54,6 +50,7 @@ function sendZoneBrightness(value) {
     brightnessSendTimeout = setTimeout(() => {
         (async () => {
             try {
+                await saveGlobalBrightnessToServer(val);
                 const section = document.querySelector('.presets-section[data-zone-id]');
                 const names = typeof window.parseTabDeviceNames === 'function'
                     ? window.parseTabDeviceNames(section)
@@ -1027,22 +1024,41 @@ document.addEventListener('DOMContentLoaded', () => {
 
     const menuBrightnessSlider = document.getElementById('menu-brightness-slider');
     const headerBrightnessSlider = document.getElementById('header-brightness-slider');
-    const savedBr = loadSavedUiBrightness();
-    if (savedBr !== null) {
-        applyBrightnessSliders(savedBr);
-    }
-    if (menuBrightnessSlider) {
-        menuBrightnessSlider.addEventListener('input', (e) => {
-            sendZoneBrightness(e.target.value);
-        });
-    }
-    if (headerBrightnessSlider) {
-        headerBrightnessSlider.addEventListener('input', (e) => {
-            sendZoneBrightness(e.target.value);
-        });
-        // Apply saved (or default) level to devices once the page is ready.
-        sendZoneBrightness(headerBrightnessSlider.value);
-    }
+    (async () => {
+        let fromServer = null;
+        try {
+            const res = await fetch('/settings', {
+                headers: { Accept: 'application/json' },
+                credentials: 'same-origin',
+            });
+            if (res.ok) {
+                const data = await res.json();
+                const g = data.global_brightness;
+                if (typeof g === 'number' && g >= 0 && g <= 255) {
+                    fromServer = Math.round(g);
+                } else if (g != null && g !== '') {
+                    const n = parseInt(String(g), 10);
+                    if (!Number.isNaN(n) && n >= 0 && n <= 255) {
+                        fromServer = n;
+                    }
+                }
+            }
+        } catch (_) {}
+        if (fromServer !== null) {
+            applyBrightnessSliders(fromServer);
+        }
+        if (menuBrightnessSlider) {
+            menuBrightnessSlider.addEventListener('input', (e) => {
+                sendZoneBrightness(e.target.value);
+            });
+        }
+        if (headerBrightnessSlider) {
+            headerBrightnessSlider.addEventListener('input', (e) => {
+                sendZoneBrightness(e.target.value);
+            });
+            sendZoneBrightness(headerBrightnessSlider.value);
+        }
+    })();
 
     // When run/edit mode toggles, refresh tabs UI so edit actions show/hide immediately.
     document.querySelectorAll('.ui-mode-toggle').forEach((btn) => {