fix(relations): filter epic ↔ task belongs_to edges from Relations panel

The epic↔task association already has dedicated UI on both sides:
the task sidebar shows an Epic field with its own selector, and the
epic page lists its tasks separately. Surfacing the auto-managed
belongs_to edge in the Relations panel just duplicated the same
information with a non-clickable raw label.

Extended enrichRelations to drop edges where kind='belongs_to' and
the endpoints are (epics, tasks) in either direction, alongside the
existing tag-edge filter. Added a regression test that creates a
linkTaskToEpic association and asserts the belongs_to edge is hidden
from both the task's and the epic's Relations panels.

Author: prih

src/lib/store-manager.ts

@@ -544,11 +544,16 @@ export class StoreManager {
    * relative to a queried entity: targetGraph, targetId, title, direction.
    * Titles are batch-resolved per graph (one SQL query per distinct graph).
    *
-   * Auto-managed `kind: 'tagged'` edges from the `tags` graph are filtered out:
-   * tags already render in their own sidebar section, and surfacing them in
-   * the Relations panel just clutters it with one row per tag. The raw edges
-   * remain available via MCP notes_list_links / tasks_list_links / etc. for
-   * LLM agents that want the full graph.
+   * Auto-managed edges are filtered out before enrichment:
+   *
+   * - `kind: 'tagged'` from/to the `tags` graph — tags already render in
+   *   their own sidebar section, and one row per tag in Relations is noise.
+   * - `kind: 'belongs_to'` between `epics` and `tasks` — the epic↔task link
+   *   has dedicated UI (Epic field in the task sidebar, task list on the epic
+   *   page), so duplicating it in Relations is noise.
+   *
+   * The raw edges remain available via MCP notes_list_links /
+   * tasks_list_links / etc. for LLM agents that want the full graph.
    */
   enrichRelations(
     entityGraph: GraphName,
@@ -561,8 +566,13 @@ export class StoreManager {
     title: string;
     direction: 'out' | 'in';
   }> {
-    // Drop auto-tagged edges before enrichment.
-    const userEdges = edges.filter(e => !(e.kind === 'tagged' && (e.fromGraph === 'tags' || e.toGraph === 'tags')));
+    // Drop auto-managed edges before enrichment.
+    const isTagEdge = (e: Edge) => e.kind === 'tagged' && (e.fromGraph === 'tags' || e.toGraph === 'tags');
+    const isEpicTaskLink = (e: Edge) =>
+      e.kind === 'belongs_to' &&
+      ((e.fromGraph === 'epics' && e.toGraph === 'tasks') ||
+       (e.fromGraph === 'tasks' && e.toGraph === 'epics'));
+    const userEdges = edges.filter(e => !isTagEdge(e) && !isEpicTaskLink(e));
     // Group target ids by their graph so we can batch-resolve titles.
     const idsByGraph = new Map<GraphName, number[]>();
     const view = userEdges.map(e => {

src/tests/store/store-manager.test.ts

@@ -571,6 +571,32 @@ describe('StoreManager', () => {
       expect(skillRel?.title).toBe('S title');
     });
 
+    it('filters out epic ↔ task belongs_to edges (have their own UI surface)', async () => {
+      // linkTaskToEpic creates an epic→task edge with kind='belongs_to'.
+      // The epic is already shown in the task sidebar (Epic field) and the
+      // epic page lists its tasks separately, so this edge would just clutter
+      // the Relations panel on either side.
+      const epic = await manager.createEpic({ title: 'Big Epic', description: '' });
+      const task = await manager.createTask({ title: 'Some task', description: '' });
+      manager.linkTaskToEpic(epic.id, task.id);
+
+      // From the task's perspective: belongs_to should NOT appear.
+      const taskEdges = [
+        ...manager.findOutgoingEdges('tasks', task.id),
+        ...manager.findIncomingEdges('tasks', task.id),
+      ];
+      const taskRels = manager.enrichRelations('tasks', task.id, taskEdges);
+      expect(taskRels.find(r => r.kind === 'belongs_to')).toBeUndefined();
+
+      // From the epic's perspective: belongs_to should NOT appear either.
+      const epicEdges = [
+        ...manager.findOutgoingEdges('epics', epic.id),
+        ...manager.findIncomingEdges('epics', epic.id),
+      ];
+      const epicRels = manager.enrichRelations('epics', epic.id, epicEdges);
+      expect(epicRels.find(r => r.kind === 'belongs_to')).toBeUndefined();
+    });
+
     it('filters out auto-tagged edges so the Relations panel stays clean', async () => {
       // Notes with tags get auto-created `tags → knowledge` edges (kind: 'tagged').
       // Tags already render in their own sidebar section; the Relations panel