fix(analysis): CPU seed queue, single waveform emit, and log URL redaction

Serialize heavy PCM seeding through a dedicated queue with optional priority
for the current track. Emit waveform-updated once per completed seed, fix
Lucky Mix waveform refresh tokens, redact Subsonic URLs in logs, and align
hot-cache prefetch with the queued path.

src/utils/redactSubsonicUrl.ts

@@ -0,0 +1,17 @@
+/**
+ * Masks Subsonic wire-auth query params so debug logs are safe to copy.
+ * (`t` salt, `s` token hash, `p` password when present.)
+ */
+export function redactSubsonicUrlForLog(url: string): string {
+  if (!url || !url.includes('stream.view')) return url;
+  try {
+    const u = new URL(url);
+    // Placeholder must stay URL-safe (no `<>` — URLSearchParams percent-encodes them).
+    for (const k of ['t', 's', 'p'] as const) {
+      if (u.searchParams.has(k)) u.searchParams.set(k, 'REDACTED');
+    }
+    return u.toString();
+  } catch {
+    return url.replace(/([?&])(t|s|p)=([^&]*)/gi, (_m, sep: string, key: string) => `${sep}${key}=REDACTED`);
+  }
+}