Add Strain Hospice for graceful low-win strain retirement.

Archive failed epidemiology strains to museum hospice with SQLite persistence, operator/AI/court triggers, breeding and graft guards, topology museum nodes, and Seer plus oath ledger accountability.

server/web/src/help/pathTracerTimeline.ts

@@ -2,6 +2,8 @@
  * Onion timeline fork/merge helpers for Path Tracer UI + Seer/AI context.
  */
 
+import { spreadStrainFromJoinLane } from './fleetTopologyEpidemiology';
+
 export type TimelineBranchStatus =
   | 'canonical'
   | 'running'
@@ -89,8 +91,28 @@ export function ghostBranchesByHop(branches: PathTraceTimelineBranch[]): Map<num
   return map;
 }
 
-export function pickMergeCandidate(branches: PathTraceTimelineBranch[]): PathTraceTimelineBranch | null {
-  const ghosts = branches.filter((b) => b.is_ghost);
+function branchPrimaryLane(branch: PathTraceTimelineBranch): string {
+  return branch.spread_lanes?.[0]?.trim() ?? '';
+}
+
+/** Spread strain from join lane — mirrors Go SpreadStrainFromJoinLane for hospice guards. */
+export function spreadStrainFromPersonaLane(lane: string): string {
+  if (!lane) return '';
+  return spreadStrainFromJoinLane(lane).toLowerCase();
+}
+
+export function pickMergeCandidate(
+  branches: PathTraceTimelineBranch[],
+  hospiceStrains?: Set<string>,
+): PathTraceTimelineBranch | null {
+  const hospice = hospiceStrains ?? new Set<string>();
+  const eligible = (b: PathTraceTimelineBranch) => {
+    const lane = branchPrimaryLane(b);
+    if (!lane || hospice.size === 0) return true;
+    const strain = spreadStrainFromPersonaLane(lane);
+    return strain === '' || !hospice.has(strain);
+  };
+  const ghosts = branches.filter((b) => b.is_ghost && eligible(b));
   const won = ghosts.find((b) => b.status === 'won' || b.mining_linked);
   if (won) return won;
   const running = ghosts.find((b) => b.status === 'running');