fix: harden media handoff and live logs

Reject stale extension media cookie headers before yt-dlp metadata work, preserve ordinary capture cookies, and advance the companion extension.

Stream redacted diagnostic logs only while the visible Logs view is active, with bounded batched updates and race-safe snapshot handoff.

src/utils/logEntries.ts

@@ -0,0 +1,92 @@
+export type LogLevel = 'Trace' | 'Debug' | 'Info' | 'Warn' | 'Error';
+
+export interface LogEntry {
+  level: LogLevel;
+  message: string;
+}
+
+export const MAX_LOG_LINES = 2000;
+
+const LEVEL_NAMES: LogLevel[] = ['Trace', 'Debug', 'Info', 'Warn', 'Error'];
+const LIVE_LEVELS: Record<number, LogLevel> = {
+  1: 'Trace',
+  2: 'Debug',
+  3: 'Info',
+  4: 'Warn',
+  5: 'Error'
+};
+
+const levelFromMessage = (message: string): LogLevel | undefined =>
+  LEVEL_NAMES.find(level => message.includes(`[${level.toUpperCase()}]`));
+
+export const persistedLogEntry = (message: string): LogEntry => ({
+  level: levelFromMessage(message) || 'Debug',
+  message
+});
+
+export const liveLogEntry = (
+  numericLevel: number,
+  message: string,
+  now: Date = new Date()
+): LogEntry => {
+  const level = levelFromMessage(message) || LIVE_LEVELS[numericLevel] || 'Debug';
+  const alreadyFormatted = /^\[\d{4}-\d{2}-\d{2}\]\[\d{2}:\d{2}:\d{2}\]\[(TRACE|DEBUG|INFO|WARN|ERROR)\]/.test(message);
+
+  return {
+    level,
+    message: alreadyFormatted
+      ? message
+      : `[${now.toISOString().replace('T', ' ').substring(0, 19)}] [${level.toUpperCase()}] ${message}`
+  };
+};
+
+export const appendBoundedLogEntries = (
+  current: LogEntry[],
+  additions: LogEntry[],
+  limit = MAX_LOG_LINES
+): LogEntry[] => {
+  if (additions.length === 0) return current;
+  const combined = [...current, ...additions];
+  return combined.length > limit ? combined.slice(combined.length - limit) : combined;
+};
+
+export const pushBoundedLogEntry = (
+  queue: LogEntry[],
+  entry: LogEntry,
+  limit = MAX_LOG_LINES
+): void => {
+  queue.push(entry);
+  if (queue.length > limit) {
+    queue.splice(0, queue.length - limit);
+  }
+};
+
+// The live target writes after the file target, so entries received while the
+// initial disk snapshot is loading can also appear at the snapshot's tail.
+// Remove only the exact ordered overlap; global message de-duplication would
+// incorrectly hide legitimate repeated log lines.
+export const mergeLogSnapshotAndLiveEntries = (
+  snapshot: LogEntry[],
+  liveEntries: LogEntry[],
+  limit = MAX_LOG_LINES
+): LogEntry[] => {
+  const maxOverlap = Math.min(snapshot.length, liveEntries.length);
+  let overlap = 0;
+
+  for (let candidate = maxOverlap; candidate > 0; candidate -= 1) {
+    const snapshotStart = snapshot.length - candidate;
+    let matches = true;
+    for (let index = 0; index < candidate; index += 1) {
+      if (snapshot[snapshotStart + index].message !== liveEntries[index].message) {
+        matches = false;
+        break;
+      }
+    }
+    if (matches) {
+      overlap = candidate;
+      break;
+    }
+  }
+
+  return appendBoundedLogEntries(snapshot, liveEntries.slice(overlap), limit);
+};