Fix SonoffLAN signing key: hardcode pre-computed HMAC key

The previous _compute_sign_key() function indexed into a base64 string
derived from the full SonoffLAN REGIONS dict (~243 entries). Our partial
dict only produced a 7876-char a string but needed index 7872+, so the
function must use the full dict.

Solution: pre-compute the key once from the full dict and hardcode the
resulting 32-byte ASCII key. This is deterministic — the SonoffLAN
algorithm always produces the same output regardless of when it runs.

The sonoff_ewelink driver now loads cleanly alongside all other drivers.

app/templates/sonoff/gateway.html

@@ -0,0 +1,260 @@
+{% extends "base.html" %}
+{% block title %}{{ board.name }} – Sonoff Gateway{% endblock %}
+
+{% block content %}
+<div class="container-fluid py-3">
+
+  {# ── Page header ──────────────────────────────────────────────────── #}
+  <div class="d-flex align-items-center justify-content-between mb-4 gap-2 flex-wrap">
+    <div class="d-flex align-items-center gap-3">
+      <a href="{{ url_for('boards.list_boards') }}" class="btn btn-outline-secondary btn-sm">
+        <i class="bi bi-arrow-left"></i>
+      </a>
+      <div>
+        <h4 class="mb-0 fw-bold">
+          <i class="bi bi-cloud-lightning-fill text-warning me-2"></i>{{ board.name }}
+        </h4>
+        <small class="text-muted">Sonoff eWeLink Gateway
+          {% if board.is_online %}
+            <span class="badge bg-success ms-2">Online</span>
+          {% else %}
+            <span class="badge bg-secondary ms-2">Offline</span>
+          {% endif %}
+        </small>
+      </div>
+    </div>
+    <div class="d-flex gap-2 flex-wrap">
+      {% if current_user.is_admin() %}
+      <form method="post" action="{{ url_for('sonoff.sync_devices', board_id=board.id) }}">
+        <button class="btn btn-primary btn-sm">
+          <i class="bi bi-arrow-repeat me-1"></i>Sync Devices
+        </button>
+      </form>
+      <a href="{{ url_for('sonoff.auth_settings', board_id=board.id) }}" class="btn btn-outline-light btn-sm">
+        <i class="bi bi-key me-1"></i>eWeLink Settings
+      </a>
+      {% endif %}
+    </div>
+  </div>
+
+  {# ── Flash messages ───────────────────────────────────────────────── #}
+  {% with messages = get_flashed_messages(with_categories=true) %}
+    {% if messages %}
+      {% for cat, msg in messages %}
+        <div class="alert alert-{{ cat }} alert-dismissible fade show py-2" role="alert">
+          {{ msg }}
+          <button type="button" class="btn-close" data-bs-dismiss="alert"></button>
+        </div>
+      {% endfor %}
+    {% endif %}
+  {% endwith %}
+
+  {# ── No credentials warning ───────────────────────────────────────── #}
+  {% if not has_credentials %}
+  <div class="alert alert-warning d-flex align-items-center gap-3" role="alert">
+    <i class="bi bi-exclamation-triangle-fill fs-4"></i>
+    <div>
+      <strong>eWeLink credentials not configured.</strong>
+      <a href="{{ url_for('sonoff.auth_settings', board_id=board.id) }}" class="alert-link">
+        Set up your account
+      </a> to discover and control devices.
+    </div>
+  </div>
+  {% endif %}
+
+  {# ── Device grid ──────────────────────────────────────────────────── #}
+  {% if devices %}
+  <div class="row g-3">
+    {% for dev in devices %}
+    <div class="col-12 col-md-6 col-xl-4" id="sonoff-card-{{ dev.device_id }}">
+      <div class="card bg-dark border-secondary h-100">
+        <div class="card-header d-flex align-items-center justify-content-between py-2">
+          <div class="d-flex align-items-center gap-2">
+            {# Kind icon #}
+            {% set kind_icon = {
+              'switch': 'bi-toggles', 'light': 'bi-lightbulb-fill',
+              'fan': 'bi-fan', 'sensor': 'bi-thermometer-half',
+              'remote': 'bi-broadcast', 'cover': 'bi-door-open'
+            }.get(dev.kind, 'bi-plug') %}
+            <i class="bi {{ kind_icon }} text-warning"></i>
+            <span class="fw-semibold text-truncate" style="max-width:160px"
+                  title="{{ dev.name }}">{{ dev.name or dev.device_id }}</span>
+          </div>
+          <div class="d-flex align-items-center gap-2">
+            {% if dev.is_online %}
+              <span class="badge bg-success">Online</span>
+            {% else %}
+              <span class="badge bg-secondary">Offline</span>
+            {% endif %}
+            <a href="{{ url_for('sonoff.device_detail', board_id=board.id, device_id=dev.device_id) }}"
+               class="btn btn-outline-secondary btn-sm px-2 py-0">
+              <i class="bi bi-sliders"></i>
+            </a>
+          </div>
+        </div>
+        <div class="card-body py-2">
+          <div class="text-muted small mb-2">
+            {{ dev.device_label }}
+            {% if dev.firmware %}<span class="ms-2 opacity-50">v{{ dev.firmware }}</span>{% endif %}
+          </div>
+
+          {# ── Switch/relay device ────────────────────────────────────── #}
+          {% if dev.kind in ('switch', 'light', 'fan') and dev.num_channels > 0 %}
+          <div class="d-flex flex-wrap gap-2">
+            {% for ch in dev.all_channel_states() %}
+            {% set ch_on = ch.state %}
+            <div class="d-flex align-items-center gap-2 border border-secondary rounded px-2 py-1"
+                 id="ch-{{ dev.device_id }}-{{ ch.channel }}"
+                 style="min-width:min-content">
+              <span class="small text-muted">{{ ch.label }}</span>
+              <div class="d-flex gap-1">
+                <button
+                  class="btn btn-sm px-2 py-0 sonoff-ch-btn {{ 'btn-success' if ch_on else 'btn-outline-success' }}"
+                  data-url="{{ url_for('sonoff.control_channel', board_id=board.id, device_id=dev.device_id, channel=ch.channel, action='on') }}"
+                  data-device="{{ dev.device_id }}" data-ch="{{ ch.channel }}" data-target="on"
+                  title="Turn ON"
+                >ON</button>
+                <button
+                  class="btn btn-sm px-2 py-0 sonoff-ch-btn {{ 'btn-danger' if not ch_on else 'btn-outline-danger' }}"
+                  data-url="{{ url_for('sonoff.control_channel', board_id=board.id, device_id=dev.device_id, channel=ch.channel, action='off') }}"
+                  data-device="{{ dev.device_id }}" data-ch="{{ ch.channel }}" data-target="off"
+                  title="Turn OFF"
+                >OFF</button>
+              </div>
+            </div>
+            {% endfor %}
+          </div>
+
+          {# ── Sensor device ──────────────────────────────────────────── #}
+          {% elif dev.kind == 'sensor' %}
+          <div class="d-flex flex-wrap gap-3">
+            {% if dev.temperature is not none %}
+            <div class="text-center">
+              <div class="fs-4 fw-bold text-info">{{ dev.temperature }}°C</div>
+              <div class="small text-muted">Temperature</div>
+            </div>
+            {% endif %}
+            {% if dev.humidity is not none %}
+            <div class="text-center">
+              <div class="fs-4 fw-bold text-primary">{{ dev.humidity }}%</div>
+              <div class="small text-muted">Humidity</div>
+            </div>
+            {% endif %}
+          </div>
+
+          {# ── Power meter ────────────────────────────────────────────── #}
+          {% if dev.has_power_meter %}
+          <div class="d-flex flex-wrap gap-3 mt-2">
+            {% if dev.power is not none %}
+            <div class="text-center">
+              <div class="fs-5 fw-bold text-warning">{{ dev.power }}W</div>
+              <div class="small text-muted">Power</div>
+            </div>
+            {% endif %}
+            {% if dev.voltage is not none %}
+            <div class="text-center">
+              <div class="fs-5 fw-bold text-success">{{ dev.voltage }}V</div>
+              <div class="small text-muted">Voltage</div>
+            </div>
+            {% endif %}
+            {% if dev.current is not none %}
+            <div class="text-center">
+              <div class="fs-5 fw-bold text-danger">{{ dev.current }}A</div>
+              <div class="small text-muted">Current</div>
+            </div>
+            {% endif %}
+          </div>
+          {% endif %}
+
+          {# ── RF Bridge / Remote ─────────────────────────────────────── #}
+          {% elif dev.kind == 'remote' %}
+          <div class="text-muted small"><i class="bi bi-broadcast me-1"></i>RF Bridge – cloud only</div>
+          {% endif %}
+
+          <div class="text-muted mt-2" style="font-size:.7rem">
+            ID: {{ dev.device_id }}
+            {% if dev.ip_address %}
+              &nbsp;·&nbsp;<i class="bi bi-wifi"></i> {{ dev.ip_address }}
+            {% endif %}
+          </div>
+        </div>
+      </div>
+    </div>
+    {% endfor %}
+  </div>
+
+  {% else %}
+  <div class="text-center py-5 text-muted">
+    <i class="bi bi-cloud-slash fs-1 d-block mb-3"></i>
+    <p class="fs-5">No devices found.</p>
+    {% if has_credentials %}
+    <form method="post" action="{{ url_for('sonoff.sync_devices', board_id=board.id) }}">
+      <button class="btn btn-primary">
+        <i class="bi bi-arrow-repeat me-1"></i>Sync from eWeLink
+      </button>
+    </form>
+    {% else %}
+    <a href="{{ url_for('sonoff.auth_settings', board_id=board.id) }}" class="btn btn-warning">
+      <i class="bi bi-key me-1"></i>Configure eWeLink Account
+    </a>
+    {% endif %}
+  </div>
+  {% endif %}
+
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script>
+const _socket = io();
+
+// ── AJAX channel control ──────────────────────────────────────────────────────
+document.querySelectorAll(".sonoff-ch-btn").forEach(btn => {
+  btn.addEventListener("click", async function() {
+    const url = this.dataset.url;
+    const did = this.dataset.device;
+    const ch  = parseInt(this.dataset.ch);
+    const tgt = this.dataset.target; // "on" or "off"
+
+    this.disabled = true;
+    try {
+      const resp = await fetch(url, {
+        method: "POST",
+        headers: { "Accept": "application/json",
+                   "X-Requested-With": "XMLHttpRequest" },
+      });
+      const data = await resp.json();
+      if (data.ok) {
+        _applyChannelState(did, ch, data.state);
+      }
+    } catch(e) { console.error(e); }
+    finally { this.disabled = false; }
+  });
+});
+
+function _applyChannelState(did, ch, isOn) {
+  const container = document.getElementById(`ch-${did}-${ch}`);
+  if (!container) return;
+  const [onBtn, offBtn] = container.querySelectorAll(".sonoff-ch-btn");
+  if (isOn) {
+    onBtn.className  = onBtn.className.replace("btn-outline-success", "btn-success");
+    offBtn.className = offBtn.className.replace("btn-danger", "btn-outline-danger");
+  } else {
+    onBtn.className  = onBtn.className.replace("btn-success", "btn-outline-success");
+    offBtn.className = offBtn.className.replace("btn-outline-danger", "btn-danger");
+  }
+}
+
+// ── SocketIO live updates ─────────────────────────────────────────────────────
+_socket.on("sonoff_update", function(data) {
+  if (data.board_id !== {{ board.id }}) return;
+  _applyChannelState(data.device_id, data.channel, data.state);
+  // Optional: flash the card border briefly
+  const card = document.getElementById("sonoff-card-" + data.device_id);
+  if (card) {
+    card.querySelector(".card").classList.add("border-info");
+    setTimeout(() => card.querySelector(".card").classList.remove("border-info"), 800);
+  }
+});
+</script>
+{% endblock %}