⬆️ Improvements & 🐛 Bug fixes

⬆️ Performance Improvement

• Fixed a major slowdown on calendar-grouped charts (#274)
• OHLC now computed only for candlestick charts. Line, bar, step and other modes skip the extra open/high/low/close pass.

🔼 🔽 Trend icon revision

• Fractional trend periods. trend_period_hours now accepts decimals (e.g. 0.5 = 30 min); previously a value like 0.5 was truncated to 0. The editor field steps in 0.05.
• Per-entity trend colours. Separate Up / Down / Stable colours for the trend icon (leave empty to follow the theme).

🍄Icons

• Template icons. The MDI icon field (card header and per-entity) now accepts Jinja templates, so the icon can change with entity state — e.g. {% if is_state('binary_sensor.door','on') %}mdi:door-open{% else %}mdi:door-closed{% endif %}. Both {{ ... }} and {% ... %} syntax are supported.

type: custom:statistics-graph-chart-card
show_legend: true
points_per_hour: 60
tooltip_match_axis: false
tooltip_order: default
height: auto
x_grid_style: dashed
y_grid_style: dashed
entities:
  - entity: sensor.keenetic_router_cpu_load
    icon: >-
      {% if states('binary_sensor.alarm_zone_5') == 'on' %}mdi:dock-bottom{%
      else %}mdi:dock-left{% endif %}
    trend_period_hours: 0.083
annotations: []

• 📋 New icon picker. A compact, themed icon dropdown in the editor with a live preview, searchable list, and direct/template text entry.

• 🎨 Theme colour picker (#272) — every colour field in the editor now has a dropdown of Home Assistant's named theme colours (Primary, Accent, Red … White) with live swatches. Picking one stores the theme-resolved colour so the chart always matches your active theme. Free-form entry (hex, rgb(), var(--x-color), threshold, entity IDs and {{ templates }}) still works via the text box + colour swatch next to it.