feat(ui): show merged-into-parent badge on adopted observations

ObservationCard renders a secondary "merged → <parent>" chip when
merged_into_project is set, next to the existing project label.
Both are meaningful: project is origin provenance, merged_into_project
is the current home.

Extends PaginationHelper's observations and summaries queries with
OR merged_into_project = ? so the single-project viewer fetch pulls
in adopted rows — the plan's Phase 3 covered multi-project context
injection; this is the single-project UI read path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ui/viewer/components/ObservationCard.tsx

@@ -56,6 +56,11 @@ export function ObservationCard({ observation }: ObservationCardProps) {
             {observation.platform_source || 'claude'}
           </span>
           <span className="card-project">{observation.project}</span>
+          {observation.merged_into_project && (
+            <span className="card-merged-badge" title={`Merged into ${observation.merged_into_project}`}>
+              merged → {observation.merged_into_project}
+            </span>
+          )}
         </div>
         <div className="view-mode-toggles">
           {hasFactsContent && (

src/ui/viewer/types.ts

@@ -2,6 +2,7 @@ export interface Observation {
   id: number;
   memory_session_id: string;
   project: string;
+  merged_into_project?: string | null;
   platform_source: string;
   type: string;
   title: string | null;