Add time remaining field, fix field pickers, auto-revert orientation, battery icon

Field pickers:
- Replaced addFieldNamePicker with addTextInput for all field
  selectors (charge, load, state, time remaining). The FieldNamePicker
  component was silently failing to render in some Grafana versions.
  Text inputs are universally supported and let users type the exact
  field name from their data source.

Time remaining:
- New 'Enable time remaining' toggle + field name in Field Mapping
- Reads the last value from the configured field (expects minutes)
- Displays as a styled card with clock icon and human-readable
  duration (e.g. '2h 15m', '45 min', '< 1 min')

Auto-revert horizontal orientation:
- When orientation is set to horizontal but the panel width is < 300px,
  automatically switches to vertical so the battery + side content
  still fit. The preference is stored, so it reverts back when the
  panel is resized larger.

Icon:
- Replaced generic Grafana scaffold logo with a battery SVG icon
  that shows in the visualisation picker and panel header.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/module.ts

@@ -5,15 +5,12 @@ import { ChargeVizOptions } from './types';
 export const plugin = new PanelPlugin<ChargeVizOptions>(ChargeVizPanel).setPanelOptions(
   (builder) => {
     // -- Field Mapping category (top) --
-    builder.addFieldNamePicker({
+    builder.addTextInput({
       path: 'chargeField',
-      name: 'Charge field',
+      name: 'Charge field name',
+      defaultValue: '',
       category: ['Field Mapping'],
-      description: 'Numeric field that represents battery charge (0–100%). If blank, the first number field is used.',
-      settings: {
-        filter: (f) => f.type === 'number',
-        noFieldsMessage: 'No numeric fields found',
-      },
+      description: 'Name of the numeric field for battery charge (0–100%). Leave blank to use the first number field.',
     });
 
     builder.addBooleanSwitch({
@@ -24,34 +21,46 @@ export const plugin = new PanelPlugin<ChargeVizOptions>(ChargeVizPanel).setPanel
       description: 'Show a second metric representing current load / power draw.',
     });
 
-    builder.addFieldNamePicker({
+    builder.addTextInput({
       path: 'loadField',
-      name: 'Load field',
+      name: 'Load field name',
+      defaultValue: '',
       category: ['Field Mapping'],
-      description: 'Numeric field for load percentage (0–100%).',
-      settings: {
-        filter: (f) => f.type === 'number',
-        noFieldsMessage: 'No numeric fields found',
-      },
+      description: 'Name of the numeric field for load percentage (0–100%).',
       showIf: (opts) => opts.enableLoad === true,
     });
 
+    builder.addBooleanSwitch({
+      path: 'enableTimeLeft',
+      name: 'Enable time remaining',
+      defaultValue: false,
+      category: ['Field Mapping'],
+      description: 'Show estimated time remaining from a data field (value in minutes).',
+    });
+
+    builder.addTextInput({
+      path: 'timeLeftField',
+      name: 'Time remaining field name',
+      defaultValue: '',
+      category: ['Field Mapping'],
+      description: 'Name of the numeric field for estimated time remaining (in minutes).',
+      showIf: (opts) => opts.enableTimeLeft === true,
+    });
+
     builder.addBooleanSwitch({
       path: 'enableStateField',
       name: 'Enable state field',
       defaultValue: false,
       category: ['Field Mapping'],
-      description: 'Use a field from the data to determine charging / discharging state instead of computing it from the rate.',
+      description: 'Use a data field to determine charging / discharging state instead of inferring from the trend.',
     });
 
-    builder.addFieldNamePicker({
+    builder.addTextInput({
       path: 'stateField',
-      name: 'State field',
+      name: 'State field name',
+      defaultValue: '',
       category: ['Field Mapping'],
-      description: 'String or numeric field whose value indicates the battery state.',
-      settings: {
-        noFieldsMessage: 'No fields found',
-      },
+      description: 'Name of the field whose value indicates battery state.',
       showIf: (opts) => opts.enableStateField === true,
     });
 
@@ -137,7 +146,7 @@ export const plugin = new PanelPlugin<ChargeVizOptions>(ChargeVizPanel).setPanel
           { value: 'horizontal', label: 'Horizontal' },
         ],
       },
-      description: 'Battery orientation. Horizontal works well in wide, short panels.',
+      description: 'Preferred orientation. Auto-reverts to vertical if the panel is too narrow for horizontal.',
     });
 
     builder.addBooleanSwitch({