fix: restore complete admin feature dependencies

src/lib/trax-format.ts

@@ -0,0 +1,63 @@
+/**
+ * Arcturus Trax format parser — client-safe (no Node-only imports).
+ *
+ * Format (verified against doorman_frank, ballad_of_bonnie, bossa_nova on a
+ * live DB):
+ *
+ *   channelN:event;event;…:channelM:event;event;…:
+ *
+ * Each `event` is `sample_id,duration`:
+ *  - sample_id = 0 means silence.
+ *  - duration = integer "ticks". One tick = 2 seconds of playback.
+ *    (Verified: doorman_frank has 24 ticks × 2s = 48s = soundtracks.length.)
+ *
+ * All channels play in parallel starting at t=0, so the total soundtrack
+ * length equals the max per-channel tick-sum × 2 seconds.
+ */
+
+export const TRAX_TICK_SECONDS = 2
+
+export interface TraxEvent {
+  sampleId: number
+  ticks: number
+}
+
+export interface TraxChannel {
+  channel: number
+  events: TraxEvent[]
+}
+
+/** Split a raw track string into per-channel event lists. */
+export function parseTraxChannels(track: string | null | undefined): TraxChannel[] {
+  if (!track) return []
+  const channels: TraxChannel[] = []
+  for (const m of track.matchAll(/(\d+):([^:]+)/g)) {
+    const channel = Number(m[1])
+    const events: TraxEvent[] = []
+    for (const raw of m[2].split(';')) {
+      const pair = raw.match(/^(\d+),(\d+)$/)
+      if (pair) events.push({ sampleId: Number(pair[1]), ticks: Number(pair[2]) })
+    }
+    if (events.length > 0) channels.push({ channel, events })
+  }
+  return channels
+}
+
+/**
+ * Parse a `track` string into the unique non-zero sample IDs it uses, sorted.
+ * Returns [] for empty or unparseable tracks (i.e. single-sample song disks).
+ */
+export function parseTrackSamples(track: string | null | undefined): number[] {
+  const set = new Set<number>()
+  for (const ch of parseTraxChannels(track)) {
+    for (const ev of ch.events) {
+      if (ev.sampleId > 0) set.add(ev.sampleId)
+    }
+  }
+  return [...set].sort((a, b) => a - b)
+}
+
+export function detectSoundtrackKind(track: string | null | undefined): 'single' | 'composition' {
+  return parseTrackSamples(track).length > 0 ? 'composition' : 'single'
+}
+