fix: Add changeset reconciliation to deleteTask and fix missing invalidation

Same orphaned-changeset pattern as deletePhase: manually deleting all
tasks from a detail changeset now marks it reverted. Also added
deleteTask to the invalidation map (was missing entirely).

apps/server/trpc/routers/task.ts

@@ -10,6 +10,7 @@ import {
   requireInitiativeRepository,
   requirePhaseRepository,
   requireDispatchManager,
+  requireChangeSetRepository,
 } from './_helpers.js';
 
 export function taskProcedures(publicProcedure: ProcedureBuilder) {
@@ -152,6 +153,29 @@ export function taskProcedures(publicProcedure: ProcedureBuilder) {
       .mutation(async ({ ctx, input }) => {
         const taskRepository = requireTaskRepository(ctx);
         await taskRepository.delete(input.id);
+
+        // Reconcile any applied changesets that created this task.
+        // If all created tasks in a changeset are now deleted, mark it reverted.
+        if (ctx.changeSetRepository) {
+          try {
+            const csRepo = requireChangeSetRepository(ctx);
+            const affectedChangeSets = await csRepo.findAppliedByCreatedEntity('task', input.id);
+            for (const cs of affectedChangeSets) {
+              const createdTaskIds = cs.entries
+                .filter(e => e.entityType === 'task' && e.action === 'create')
+                .map(e => e.entityId);
+              const survivingTasks = await Promise.all(
+                createdTaskIds.map(id => taskRepository.findById(id)),
+              );
+              if (survivingTasks.every(t => t === null)) {
+                await csRepo.markReverted(cs.id);
+              }
+            }
+          } catch {
+            // Best-effort reconciliation — don't fail the delete
+          }
+        }
+
         return { success: true };
       }),
 

apps/web/src/lib/invalidation.ts

@@ -65,6 +65,8 @@ const INVALIDATION_MAP: Partial<Record<MutationName, QueryName[]>> = {
   createChildTasks: ["listTasks", "listInitiativeTasks", "listPhaseTasks"],
   queueTask: ["listTasks", "listInitiativeTasks", "listPhaseTasks"],
 
+  deleteTask: ["listTasks", "listInitiativeTasks", "listPhaseTasks", "listChangeSets"],
+
   // --- Change Sets ---
   revertChangeSet: ["listPhases", "listPhaseTasks", "listInitiativeTasks", "listPages", "getPage", "listChangeSets", "getRootPage"],