Add Path Tracer onion timeline fork/merge with ghost branches and Seer feed.

Operators fork at hop N to run persona ensembles in parallel on the target agent until mining links; winners merge back into the canonical SQLite-persisted session with WS and Seer events plus mermaid branch graphs in the UI.

server/web/src/help/seerEvents.ts

@@ -0,0 +1,56 @@
+/** Seer feed event from WS `seer_events` or GET /api/v1/seer/stream. */
+export interface SeerEventRecord {
+  id?: number;
+  event_type: string;
+  agent_id?: string;
+  payload?: Record<string, unknown>;
+  ts?: string;
+}
+
+export function isPathTraceTimelineEvent(event: SeerEventRecord): boolean {
+  return event.event_type === 'pathtrace_timeline';
+}
+
+export function pathTraceTimelineSummary(event: SeerEventRecord): string {
+  if (!isPathTraceTimelineEvent(event)) return '';
+  const p = event.payload ?? {};
+  const ev = typeof p.event === 'string' ? p.event : 'update';
+  const branch = p.branch as { persona?: string; status?: string; hashrate?: number } | undefined;
+  if (ev === 'fork') return 'Path Tracer fork — ghost branches spawned';
+  if (ev === 'branch_won') {
+    return `Path Tracer branch won (${branch?.persona ?? 'unknown'})${branch?.hashrate ? ` · ${Math.round(branch.hashrate)} H/s` : ''}`;
+  }
+  if (ev === 'merge') return `Path Tracer merged ${branch?.persona ?? 'winner'} into canonical timeline`;
+  return `Path Tracer timeline ${ev}`;
+}
+
+export function isSurgicalReplayEvent(event: SeerEventRecord): boolean {
+  return event.event_type === 'surgical_replay';
+}
+
+export function surgicalReplaySummary(event: SeerEventRecord): string {
+  if (!isSurgicalReplayEvent(event)) {
+    return '';
+  }
+  const p = event.payload ?? {};
+  const tier = typeof p.failed_tier === 'string' ? p.failed_tier : 'tier';
+  const fix = typeof p.fix_type === 'string' ? p.fix_type : 'fix';
+  const outcome = typeof p.outcome === 'string' ? p.outcome : '';
+  return `Surgical replay ${tier} → ${fix}${outcome ? ` (${outcome})` : ''}`;
+}
+
+export function mergeSeerEvents(
+  existing: SeerEventRecord[],
+  incoming: SeerEventRecord | SeerEventRecord[],
+): SeerEventRecord[] {
+  const batch = Array.isArray(incoming) ? incoming : [incoming];
+  const seen = new Set(existing.map((e) => `${e.id ?? ''}:${e.event_type}:${e.ts ?? ''}`));
+  const merged = [...existing];
+  for (const ev of batch) {
+    const key = `${ev.id ?? ''}:${ev.event_type}:${ev.ts ?? ''}`;
+    if (seen.has(key)) continue;
+    seen.add(key);
+    merged.unshift(ev);
+  }
+  return merged.slice(0, 200);
+}