feat(ST-804): solo-store realtime dispatch + pendingOps

Wire de SSE-events uit /api/realtime/solo door naar de Zustand-store
zodat het Solo Paneel zonder refresh meebeweegt met DB-mutaties uit
welke bron dan ook (web, REST, MCP).

Migratie 20260427000216_extend_realtime_payload: voegt new-state
velden aan de pg_notify-payload toe (task_status, task_sort_order,
task_title, story_status, story_sort_order, story_title, story_code)
zodat de client geen extra fetch nodig heeft per event.

Store-uitbreiding (stores/solo-store.ts):
- pendingOps: Set<task-id> die optimistic-writes markeert; realtime
  echos voor die ids worden onderdrukt zodat eigen UI-mutaties niet
  twee keer toegepast worden of door een latere echo overschreven
- handleRealtimeEvent: dispatch op entity + op
  - task UPDATE/INSERT: bestaande tasks krijgen status/title/sort_order
    bijgewerkt; onbekende tasks worden genegeerd (story-context
    ontbreekt — gebruiker ziet ze pas na refresh)
  - task DELETE: verwijdert uit store
  - story UPDATE: werkt story_title/story_code bij op alle child-tasks
    in de store
  - story DELETE: verwijdert alle child-tasks (cascade reflectie)

Unit-test: 7 scenario's (status update, pendingOps echo-suppression,
DELETE, story-rename cascade, story-delete cascade, unknown task
no-op).

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

prisma/migrations/20260427000216_extend_realtime_payload/migration.sql

@@ -0,0 +1,111 @@
+-- ST-804 prereq: extend the realtime trigger payload with the new-state
+-- fields the Solo Paneel needs for in-place rendering, so the client doesn't
+-- have to refetch on every update.
+--
+-- Added fields:
+--   task   → task_status, task_sort_order, task_title
+--   story  → story_status, story_sort_order, story_title, story_code
+--
+-- Description and implementation_plan stay out of the payload — they can
+-- be large and aren't needed for kanban-board rendering. UI fetches them
+-- on demand when the detail dialog opens.
+
+CREATE OR REPLACE FUNCTION notify_task_change() RETURNS trigger AS $$
+DECLARE
+  rec record;
+  story_row record;
+  payload jsonb;
+BEGIN
+  IF TG_OP = 'DELETE' THEN
+    rec := OLD;
+  ELSE
+    rec := NEW;
+  END IF;
+
+  SELECT product_id, sprint_id, assignee_id
+    INTO story_row
+    FROM stories
+    WHERE id = rec.story_id;
+
+  IF NOT FOUND THEN
+    RETURN rec;
+  END IF;
+
+  payload := jsonb_build_object(
+    'op', CASE TG_OP
+            WHEN 'INSERT' THEN 'I'
+            WHEN 'UPDATE' THEN 'U'
+            WHEN 'DELETE' THEN 'D'
+          END,
+    'entity', 'task',
+    'id', rec.id,
+    'story_id', rec.story_id,
+    'product_id', story_row.product_id,
+    'sprint_id', story_row.sprint_id,
+    'assignee_id', story_row.assignee_id,
+    'task_status', rec.status,
+    'task_sort_order', rec.sort_order,
+    'task_title', rec.title
+  );
+
+  IF TG_OP = 'UPDATE' THEN
+    payload := payload || jsonb_build_object(
+      'changed_fields',
+      COALESCE((
+        SELECT jsonb_agg(n.key)
+        FROM jsonb_each(to_jsonb(NEW)) n
+        JOIN jsonb_each(to_jsonb(OLD)) o USING (key)
+        WHERE n.value IS DISTINCT FROM o.value
+      ), '[]'::jsonb)
+    );
+  END IF;
+
+  PERFORM pg_notify('scrum4me_changes', payload::text);
+  RETURN rec;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE OR REPLACE FUNCTION notify_story_change() RETURNS trigger AS $$
+DECLARE
+  rec record;
+  payload jsonb;
+BEGIN
+  IF TG_OP = 'DELETE' THEN
+    rec := OLD;
+  ELSE
+    rec := NEW;
+  END IF;
+
+  payload := jsonb_build_object(
+    'op', CASE TG_OP
+            WHEN 'INSERT' THEN 'I'
+            WHEN 'UPDATE' THEN 'U'
+            WHEN 'DELETE' THEN 'D'
+          END,
+    'entity', 'story',
+    'id', rec.id,
+    'product_id', rec.product_id,
+    'sprint_id', rec.sprint_id,
+    'assignee_id', rec.assignee_id,
+    'story_status', rec.status,
+    'story_sort_order', rec.sort_order,
+    'story_title', rec.title,
+    'story_code', rec.code
+  );
+
+  IF TG_OP = 'UPDATE' THEN
+    payload := payload || jsonb_build_object(
+      'changed_fields',
+      COALESCE((
+        SELECT jsonb_agg(n.key)
+        FROM jsonb_each(to_jsonb(NEW)) n
+        JOIN jsonb_each(to_jsonb(OLD)) o USING (key)
+        WHERE n.value IS DISTINCT FROM o.value
+      ), '[]'::jsonb)
+    );
+  END IF;
+
+  PERFORM pg_notify('scrum4me_changes', payload::text);
+  RETURN rec;
+END;
+$$ LANGUAGE plpgsql;