feat(FN-1044): add thinkingLevel and planning model support to task creation

- Add thinkingLevel field to createTask and updateTask in core store
- Accept thinkingLevel and planningModel fields in dashboard task routes
- Send thinkingLevel and planningModel in frontend API calls from task forms
- Add ThinkingLevel selector to ModelSelectorTab component with tests
- Wire up planning model and thinking level in QuickEntryBox, TaskForm, and NewTaskModal
- Add unit tests for store, routes, and ModelSelectorTab coverage
- Add changeset and update AGENTS.md documentation

packages/core/src/store.test.ts

@@ -1330,6 +1330,44 @@ describe("TaskStore", () => {
       expect(updated.missionId).toBe("M-789");
       expect(updated.sliceId).toBe("SL-789");
     });
+
+    it("sets thinkingLevel via createTask and updateTask", async () => {
+      const created = await store.createTask({
+        description: "Task with thinking level",
+        thinkingLevel: "high",
+      });
+      expect(created.thinkingLevel).toBe("high");
+
+      const persisted = await store.getTask(created.id);
+      expect(persisted.thinkingLevel).toBe("high");
+
+      const updated = await store.updateTask(created.id, { thinkingLevel: "low" });
+      expect(updated.thinkingLevel).toBe("low");
+
+      const reloaded = await store.getTask(created.id);
+      expect(reloaded.thinkingLevel).toBe("low");
+    });
+
+    it("clears thinkingLevel via null in updateTask", async () => {
+      const task = await store.createTask({
+        description: "Task with thinking level",
+        thinkingLevel: "medium",
+      });
+      expect(task.thinkingLevel).toBe("medium");
+
+      const updated = await store.updateTask(task.id, { thinkingLevel: null });
+      expect(updated.thinkingLevel).toBeUndefined();
+    });
+
+    it("preserves thinkingLevel when updating unrelated fields", async () => {
+      const task = await store.createTask({
+        description: "Task with thinking level",
+        thinkingLevel: "high",
+      });
+      const updated = await store.updateTask(task.id, { title: "Updated title" });
+      expect(updated.thinkingLevel).toBe("high");
+      expect(updated.title).toBe("Updated title");
+    });
   });
 
   describe("updateTask — PROMPT.md regeneration", () => {

packages/core/src/store.ts

@@ -836,6 +836,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
       validatorModelId: input.validatorModelId,
       planningModelProvider: input.planningModelProvider,
       planningModelId: input.planningModelId,
+      thinkingLevel: input.thinkingLevel,
       steps: [],
       currentStep: 0,
       log: [{ timestamp: now, action: "Task created" }],
@@ -1123,7 +1124,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
 
   async updateTask(
     id: string,
-    updates: { title?: string; description?: string; prompt?: string; worktree?: string | null; status?: string | null; dependencies?: string[]; blockedBy?: string | null; paused?: boolean; baseBranch?: string | null; branch?: string | null; baseCommitSha?: string | null; size?: "S" | "M" | "L"; reviewLevel?: number; mergeRetries?: number; stuckKillCount?: number | null; recoveryRetryCount?: number | null; nextRecoveryAt?: string | null; enabledWorkflowSteps?: string[]; modelProvider?: string | null; modelId?: string | null; validatorModelProvider?: string | null; validatorModelId?: string | null; planningModelProvider?: string | null; planningModelId?: string | null; error?: string | null; summary?: string | null; sessionFile?: string | null; workflowStepResults?: import("./types.js").WorkflowStepResult[] | null; mergeDetails?: import("./types.js").MergeDetails | null; modifiedFiles?: string[] | null; missionId?: string | null; sliceId?: string | null },
+    updates: { title?: string; description?: string; prompt?: string; worktree?: string | null; status?: string | null; dependencies?: string[]; blockedBy?: string | null; paused?: boolean; baseBranch?: string | null; branch?: string | null; baseCommitSha?: string | null; size?: "S" | "M" | "L"; reviewLevel?: number; mergeRetries?: number; stuckKillCount?: number | null; recoveryRetryCount?: number | null; nextRecoveryAt?: string | null; enabledWorkflowSteps?: string[]; modelProvider?: string | null; modelId?: string | null; validatorModelProvider?: string | null; validatorModelId?: string | null; planningModelProvider?: string | null; planningModelId?: string | null; thinkingLevel?: string | null; error?: string | null; summary?: string | null; sessionFile?: string | null; workflowStepResults?: import("./types.js").WorkflowStepResult[] | null; mergeDetails?: import("./types.js").MergeDetails | null; modifiedFiles?: string[] | null; missionId?: string | null; sliceId?: string | null },
   ): Promise<Task> {
     return this.withTaskLock(id, async () => {
       // Validate that task doesn't depend on itself
@@ -1241,6 +1242,11 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
       } else if (updates.planningModelId !== undefined) {
         task.planningModelId = updates.planningModelId;
       }
+      if (updates.thinkingLevel === null) {
+        task.thinkingLevel = undefined;
+      } else if (updates.thinkingLevel !== undefined) {
+        task.thinkingLevel = updates.thinkingLevel as import("./types.js").ThinkingLevel;
+      }
       if (updates.error === null) {
         task.error = undefined;
       } else if (updates.error !== undefined) {