Widget branding: remove the profile picture, themes that behave

Under Channels → Widget → Style → Brand, the profile picture — the avatar in the chat header — now has three explicit states. Upload your own (JPG, PNG, or SVG up to 1MB), inherit your workspace logo (the default), or select Remove. Removed means removed: as the helper text puts it, “Removed — the chat header shows the Asks mark instead.” No avatar is forced on a widget that doesn't want one.

The theme system got stricter. Per-token colors — the composer input's background and text, accent text, links — used to leak into the Light and Dark presets, so a workspace that had once experimented with Custom could end up with a dark composer sitting in a light widget. Those tokens now apply only when your theme is actually Custom; Light and Dark render their designed palettes exactly. Surfaces painted with your primary color also pick a contrasting ink automatically, so text stays readable whatever color you choose.

• The widget preview's customer bubble now matches the live widget exactly — what you style is what ships.
• The greeting field became a multi-line textarea, so a two-line opening message no longer has to be written blind.
• The “primary color too light” warning now compares your color against the actual chat background rather than assuming white — dark-themed widgets stop getting false alarms.