Canonical Live Presets

Parent sub-epic: #2187 ## Context After the canonical on-demand Video preset proves the shared delivery path, add Default and Minimal live-video and live-audio presets. Live presets reuse shared presentation and controls while replacing VOD timeline behavior with live status, using smaller input-binding subsets, and omitting seek-only feedback. This is a placeholder delivery epic. Split reusable live components, video/audio composition, validation, and cutover into focused children when this preset becomes active. LiveButton is tracked in #2115. ## Acceptance boundary - Canonical live-video compositions preserve live status, captions, remote controls, presentation, feedback, and appropriate input bindings. - Canonical live-audio compositions preserve play/live/volume layout, buffering/error behavior, hotkeys, and announcements. - VOD-only timeline and seek behavior is not inherited accidentally. - Default and Minimal reuse shared behavior and fork only for meaningful structure or styles. - React/HTML and Tailwind/vanilla CSS follow the proven delivery path. - Legacy live implementations are removed only after interaction, accessibility, responsive, and visual parity.