Call parts: ControlButton, ParticipantTile, FloatingDock, IncomingCallCard, BottomSheet, Slider export

[prakashUXtech]

Adds the parts paw-enterprise needs to build its three call layouts (Glass, Focus, Classic). Every part is a new ./ui-only export, so the spec registry and the manifest don't change (still 189 widgets). No media and no LiveKit in ripple: the tile takes the host's <video> through a snippet.

Export (@ripple-ui/svelte/ui)	What it does	Props
ControlButton	one call control, native <button>, forwards every attribute	variant pill / bar / classic, tone default / danger / accent, size default / compact, pressed (aria-pressed), wide (hang-up), label (text beside the icon, bar only, hidden under 640px), icon snippet, count / mention / badgeTestId
ControlBar	the row the buttons sit in, role=group	label, variant pill / bar / classic, size default / compact
CountBadge	count pill: N, 99+ over 99, @ for a mention, nothing at 0	count, mention, max, any span attribute (keeps host test ids)
ParticipantTile	one person: video slot, ripple Avatar fallback, name pill, mic-off, speaking state	name, src, speaking, muted, skin glass / focus / classic, size lg / md / sm / orb; snippets video, avatar, badge, menu
FloatingDock	draggable container: pointer capture, ignores drags that start on controls, snaps to the nearer side, clamps on drop and on window resize	label, corner, bounds window / parent, gap, onPositionChange
IncomingCallCard	incoming / joinable / rejoin card with a pulsing halo (Tailwind's animate-ping, motion-safe)	title, subtitle, name, src, role (alert by default), halo; snippets avatar, primary, secondary
BottomSheet	non-modal sheet with peek / half / full stops. Drag the handle past 48px to move a stop, under 6px counts as a tap. Enter/Space toggle, arrow keys step. Content stays mounted	stop (bindable, mirrored to data-state), onStopChange, label, handleLabel(stop), handleTestId
Slider	the existing shadcn slider, now exported as a namespace (Slider.Root)	bits-ui props

The primitives Button (@ripple-ui/svelte/primitives) also gets a success variant for Accept and Join.

Colours are ripple tokens only. Accent text on glass reads --ripple-accent-on-glass if the host defines it and falls back to --ripple-accent. Sizes live in scoped CSS, so a Tailwind w-* class won't resize a ControlButton. Use wide for that.

Tests

widgets/call/call.test.ts has 26 behaviour tests, committed red first. The ./ui contract test now mounts every new export standalone and lists Slider as a namespace. The full svelte suite passes (1471 tests). bun run check: 0 errors, 0 warnings. bun run lint: clean apart from the usual test-file assertion warnings. Root bun run build passes and the manifest is unchanged. /showcase/call shows every part in all three layouts. I clicked through it in a browser: layout switch, speaker ring per skin, bar labels, wide hang-up, sheet stops, halo animation.

Not verified

• The dock drag was only tested in jsdom with stubbed rects. Nobody has dragged it by hand yet.
• The 640px label hide and the glass blur in paw-enterprise's light theme under its glass pin haven't been checked. That happens when PE consumes these parts.
• One Qr security test failed once in a full run and passed on rerun, and it passes alone on both this branch and main. I think it's a flake and not caused by this PR.