Add WiFi and HDMI power saving features for remote sensors

Implements power saving optimizations to extend battery life on solar-powered remote air quality sensors:

- WiFi Power Saving: Disable WiFi 10 minutes after boot to save ~100-200mA
  - Configurable via web UI checkbox in admin panel
  - WiFi automatically re-enables after reboot for 10-minute configuration window
  - Systemd timer (nebuleair-wifi-powersave.timer) manages automatic disable
  - New wifi/power_save.py script checks database config and disables WiFi via nmcli

- HDMI Disable: Added hdmi_blanking=2 to boot config to save ~20-30mA
  - Automatically configured during installation

- Database: Added wifi_power_saving boolean config (default: disabled)
  - Uses INSERT OR IGNORE for safe updates to existing installations

- UI: Added checkbox control in admin.html for WiFi power saving
  - Includes helpful description of power savings and behavior

- Services: Updated setup_services.sh and update_firmware.sh to manage new timer

Total power savings: ~120-230mA when WiFi power saving enabled

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

wifi/power_save.py

@@ -0,0 +1,128 @@
+#!/usr/bin/env python3
+r'''
+ __        ___ ___ ___   ____
+ \ \      / (_)  _(_) | |  _ \ _____      _____ _ __
+  \ \ /\ / /| | | | | | | |_) / _ \ \ /\ / / _ \ '__|
+   \ V  V / | | | | | | |  __/ (_) \ V  V /  __/ |
+    \_/\_/  |_|_| |_|_| |_|    \___/ \_/\_/ \___|_|
+      ____
+     / ___|  __ ___   _____
+     \___ \ / _` \ \ / / _ \
+      ___) | (_| |\ V /  __/
+     |____/ \__,_| \_/ \___|
+
+WiFi Power Saving Script
+Disables WiFi after 10 minutes of boot if wifi_power_saving is enabled in config.
+Saves ~100-200mA of power consumption.
+
+Usage:
+/usr/bin/python3 /var/www/nebuleair_pro_4g/wifi/power_save.py
+'''
+
+import sqlite3
+import subprocess
+import sys
+import datetime
+
+# Paths
+DB_PATH = "/var/www/nebuleair_pro_4g/sqlite/sensors.db"
+LOG_PATH = "/var/www/nebuleair_pro_4g/logs/app.log"
+
+def log_message(message):
+    """Write message to log file with timestamp"""
+    timestamp = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
+    log_entry = f"[{timestamp}] [WiFi Power Save] {message}\n"
+    try:
+        with open(LOG_PATH, "a") as log_file:
+            log_file.write(log_entry)
+    except Exception as e:
+        print(f"Failed to write to log: {e}", file=sys.stderr)
+    print(log_entry.strip())
+
+def get_config_value(key):
+    """Read configuration value from database"""
+    try:
+        conn = sqlite3.connect(DB_PATH)
+        cursor = conn.cursor()
+        cursor.execute("SELECT value FROM config_table WHERE key = ?", (key,))
+        result = cursor.fetchone()
+        conn.close()
+        return result[0] if result else None
+    except sqlite3.Error as e:
+        log_message(f"Database error: {e}")
+        return None
+
+def is_wifi_enabled():
+    """Check if WiFi radio is currently enabled"""
+    try:
+        result = subprocess.run(
+            ["nmcli", "radio", "wifi"],
+            capture_output=True,
+            text=True,
+            timeout=10
+        )
+        return result.stdout.strip() == "enabled"
+    except Exception as e:
+        log_message(f"Failed to check WiFi status: {e}")
+        return None
+
+def disable_wifi():
+    """Disable WiFi radio using nmcli"""
+    try:
+        result = subprocess.run(
+            ["sudo", "nmcli", "radio", "wifi", "off"],
+            capture_output=True,
+            text=True,
+            timeout=10
+        )
+        if result.returncode == 0:
+            log_message("WiFi disabled successfully - saving ~100-200mA power")
+            return True
+        else:
+            log_message(f"Failed to disable WiFi: {result.stderr}")
+            return False
+    except subprocess.TimeoutExpired:
+        log_message("Timeout while trying to disable WiFi")
+        return False
+    except Exception as e:
+        log_message(f"Error disabling WiFi: {e}")
+        return False
+
+def main():
+    """Main function"""
+    log_message("WiFi power save script started")
+
+    # Check if wifi_power_saving is enabled in config
+    wifi_power_saving = get_config_value("wifi_power_saving")
+
+    if wifi_power_saving is None:
+        log_message("wifi_power_saving config not found - skipping (run migration or set_config.py)")
+        return 0
+
+    if wifi_power_saving == "0":
+        log_message("WiFi power saving is disabled in config - WiFi will remain enabled")
+        return 0
+
+    log_message("WiFi power saving is enabled in config")
+
+    # Check current WiFi status
+    wifi_enabled = is_wifi_enabled()
+    if wifi_enabled is None:
+        log_message("Could not determine WiFi status - aborting")
+        return 1
+
+    if not wifi_enabled:
+        log_message("WiFi is already disabled - nothing to do")
+        return 0
+
+    # Disable WiFi
+    log_message("Disabling WiFi after 10-minute configuration window...")
+    if disable_wifi():
+        log_message("WiFi power save completed successfully")
+        return 0
+    else:
+        log_message("WiFi power save failed")
+        return 1
+
+if __name__ == "__main__":
+    sys.exit(main())