Add console restrictions documentation and update client console HTML

Added CONSOLE_RESTRICTIONS.md to document which hardware-related settings are locked in the client console and how to change them. Updated CLIENT_CONSOLE_HTML in the main firmware to match the latest UI and restrictions, ensuring hardware configuration fields are properly described and handled.

Author: dorkmo

TankAlarm-112025-Server-BluesOpta/CONSOLE_RESTRICTIONS.md

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+# Console Restrictions & Hardware Configuration
+
+The **Client Console** web interface allows remote configuration of alarm thresholds, reporting schedules, and site metadata. However, settings that define the **physical hardware interface** (wiring, sensors, pins) are **locked** in the console to prevent accidental misconfiguration that could disable monitoring or require a site visit to fix.
+
+These settings must be defined in the initial configuration file uploaded to the device (e.g., via USB or SD card) or compiled into the firmware.
+
+## Locked Settings (Hardware Dependent)
+
+The following settings are visible in the console but cannot be edited:
+
+### 1. Clear Button Configuration
+*   **Clear Button Pin**: The physical GPIO pin connected to the external push-button.
+*   **Button Active State**: The electrical logic level (Active HIGH vs Active LOW) determined by the wiring (pull-up vs pull-down resistors).
+
+### 2. Tank Sensor Configuration
+*   **Sensor Type**: The class of sensor hardware installed (e.g., `Analog` 4-20mA, `Digital` Float Switch, `Current Loop`). Changing this requires different physical wiring and often different driver circuitry.
+*   **Primary Pin**: The main GPIO or Analog pin where the sensor signal is read.
+*   **Secondary Pin**: Used for differential readings or complex sensors.
+*   **Loop Channel**: For multiplexed current loop sensors (e.g., using an external ADC or Mux).
+
+## How to Change Hardware Settings
+
+To modify these settings, you must update the device configuration file directly.
+
+1.  **Create/Edit Config File**: Generate a `client_config.json` file with the correct hardware parameters.
+2.  **Upload**:
+    *   **Option A (SD Card)**: Save the file to an SD card and insert it into the device. Reboot to load.
+    *   **Option B (USB)**: Connect via USB Serial and use the CLI command `config set <json_payload>`.
+    *   **Option C (Firmware)**: If using a fixed fleet deployment, update the default configuration in `TankAlarm-112025-Client-BluesOpta.ino` and re-flash the device.
+
+## Why are these locked?
+
+*   **Safety**: Changing a pin assignment remotely to a pin that is driving a relay or other actuator could cause hardware damage.
+*   **Reliability**: Incorrect sensor types will result in false alarms or zero readings.
+*   **Stability**: These settings rarely change after installation. Locking them prevents "fat-finger" errors during routine threshold adjustments.