Rewrite dashboard and overlay, single /events stream, static client served by the backend

Backend: one SSE stream for messages, selection, poll and connection status; reconnect with backoff; no on-disk Innertube session cache; mock only with MOCK_CHAT=1; binds to 127.0.0.1; serves client/out so production runs on one port. Full URLs for links YouTube truncates in chat.

Client: components split out, Lucide icons, stream title and status, on-air strip, search, pause, keyboard shortcuts, overlay settings dialog. Overlay themes, position, size, animation and auto-hide via URL, sized for 1080p and scaled with the source. New blueprint theme for the brand background.

Removed Tailwind, better-sqlite3, zod, the timezone helpers, Cline memory bank and AGENTS.md. Added ESLint, node:test tests and CI.

client/lib/useEvents.ts

@@ -0,0 +1,91 @@
+'use client';
+
+import { useEffect, useReducer } from 'react';
+import type { ChatMessage, ConnectionStatus, Poll, ServerEvent, ServerEventType } from '@shared/chat';
+import { BACKEND_URL } from './config';
+
+export type StreamState = 'connecting' | 'open' | 'error';
+
+export type EventsState = {
+  stream: StreamState;
+  status: ConnectionStatus;
+  messages: ChatMessage[];
+  selection: ChatMessage | null;
+  poll: Poll | null;
+};
+
+const MAX_REGULAR = 200;
+const EVENT_TYPES: ServerEventType[] = ['init', 'message', 'selection', 'poll', 'status', 'clear'];
+
+const initialState: EventsState = {
+  stream: 'connecting',
+  status: { state: 'disconnected', liveId: null },
+  messages: [],
+  selection: null,
+  poll: null
+};
+
+export function isSpecial(message: ChatMessage): boolean {
+  return !!(message.superChat || message.membershipGift || message.membershipGiftPurchase);
+}
+
+/** Appends a message and drops the oldest regular ones past the cap. Special messages are always kept. */
+function append(list: ChatMessage[], message: ChatMessage): ChatMessage[] {
+  const next = [...list, message];
+  let regular = 0;
+  for (const item of next) if (!isSpecial(item)) regular += 1;
+  let drop = regular - MAX_REGULAR;
+  if (drop <= 0) return next;
+  return next.filter((item) => {
+    if (drop > 0 && !isSpecial(item)) {
+      drop -= 1;
+      return false;
+    }
+    return true;
+  });
+}
+
+type Action = ServerEvent | { type: 'stream'; stream: StreamState };
+
+function reducer(state: EventsState, action: Action): EventsState {
+  switch (action.type) {
+    case 'stream':
+      return { ...state, stream: action.stream };
+    case 'init':
+      return { ...state, status: action.status, messages: action.messages, selection: action.selection, poll: action.poll };
+    case 'message':
+      return { ...state, messages: append(state.messages, action.message) };
+    case 'selection':
+      return { ...state, selection: action.message };
+    case 'poll':
+      return { ...state, poll: action.poll };
+    case 'status':
+      return { ...state, status: action.status };
+    case 'clear':
+      return { ...state, messages: [], selection: null, poll: null };
+    default:
+      return state;
+  }
+}
+
+/** Single SSE subscription to the backend. EventSource reconnects on its own and the server replays state on `init`. */
+export function useEvents(): EventsState {
+  const [state, dispatch] = useReducer(reducer, initialState);
+
+  useEffect(() => {
+    const source = new EventSource(`${BACKEND_URL}/events`);
+    const onEvent = (event: Event) => {
+      try {
+        dispatch(JSON.parse((event as MessageEvent).data));
+      } catch (error) {
+        console.error('Bad event payload', error);
+      }
+    };
+    for (const type of EVENT_TYPES) source.addEventListener(type, onEvent);
+    source.onopen = () => dispatch({ type: 'stream', stream: 'open' });
+    source.onerror = () => dispatch({ type: 'stream', stream: 'error' });
+    return () => source.close();
+  }, []);
+
+  return state;
+}