Add label_icon_color support for label icons

[aw1604]

Add label_icon_color option to style label icons individually

This PR adds support for an additional per-entity configuration option:

label_icon_color: "#rrggbb"

This allows users to set the color of label icons (e.g. mdi: icons) independently from the event text color.
Currently, the label always inherits the default text color, which prevents proper color-coding of different event types.

✔️Key changes:

• Added new config property: label_icon_color
• Updated types.ts and config.ts to include the new option
• Updated renderLabel() to accept and apply inline color styling
• Updated event rendering so the matched entity config passes label_icon_color correctly
• No breaking changes

Example usage:

entities:

• entity: calendar.abfallkalender
  allowlist: Biotonne
  label: mdi:flower-outline
  label_icon_color: "#966919"

✔️ Backward compatibility

Fully backward compatible, if label_icon_color is omitted, the default behavior is unchanged.

✔️ Testing

Verified in Home Assistant 2025.11.3 with the latest Calendar Card Pro.

Tested with MDI icons

Works with allowlist/blocklist matching and entity overrides.