✨ Premium chat designs, citations & customizable contact collection

🎨 New chat-window designs

Pick a look that matches your brand — the current style is kept as Legacy, and five new premium presets are now selectable per agent:

Glass — frosted dark glass with soft glow and rounded bubbles
Terminal — monospace developer style, square corners
Playful — light, friendly, very rounded with warm accents
Calm Mint — clean dark-teal with subtle borders
Aurora — dark ask-me-anything with a glowing orb avatar
The design picker groups Legacy vs New with live thumbnails, selecting a design seeds a matching color palette you can still customize, and every theme gets a polished finish with message entrance + "reading knowledge base" animations (honoring prefers-reduced-motion).

📎 Knowledge-base citations
A new Show citations toggle displays the knowledge sources used to answer, as chips under each reply — so visitors can see what the answer was grounded in.

📨 Customizable contact collection
Pre-chat email is now optional. Off by default — visitors can start chatting immediately. Turn on Collect email before chat to require an email first.
Capture contact at human handoff. When a chat transfers to a human (or a ticket is created because no agents are online), an inline form collects the visitor's email (toggleable) and name (optional) and saves it to the customer record so your team can follow up.
The agent no longer exposes the internal anonymous placeholder address — instead of promising to email …@noemail.com, it asks for real contact details via the form.
🟢 New brand mark
Refreshed the ChatterMate icon to the new lime three-dot mark across the favicon set, logos, the widget launcher button, and the web manifest.

🛠 Improvements & fixes
Dark themes now render correctly end-to-end: readable agent bubbles, inputs, contact forms, dividers, and overlays (no more white-on-dark).
Theme-accent input borders instead of generic gray/white.
More compact message bubbles in the embedded widget.
Aurora's avatar follows the agent's profile picture (orb only as the no-photo fallback).
Fixed form fields stealing focus back to the message box; better-aligned validation messages.
🗄 Database
Adds idempotent migrations for: new chatstyle enum values (Glass/Terminal/Playful/Calm Mint/Aurora), show_citations, collect_email, and handoff_collect_email / handoff_collect_name.

📦 Notes
Defaults: pre-chat email off; handoff email on, name on; citations on.
Enterprise (Shopify) customization gains the Collect email before chat toggle (see enterprise_frontend#4).