feat(planner): integrate C4 RecipePicker with PanelState machine + slot actions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/(app)/planner/page.server.test.ts

@@ -6,8 +6,10 @@ vi.mock('$env/dynamic/private', () => ({
 
 const mockGet = vi.fn();
 const mockPost = vi.fn();
+const mockPatch = vi.fn();
+const mockDelete = vi.fn();
 vi.mock('$lib/server/api', () => ({
-	apiClient: () => ({ GET: mockGet, POST: mockPost })
+	apiClient: () => ({ GET: mockGet, POST: mockPost, PATCH: mockPatch, DELETE: mockDelete })
 }));
 
 describe('planner page — load', () => {
@@ -193,3 +195,89 @@ describe('planner page — variety score partial failure', () => {
 		expect(result.varietyScore).toBeNull();
 	});
 });
+
+describe('planner page — slot actions', () => {
+	let actions: any;
+
+	beforeEach(async () => {
+		mockGet.mockReset();
+		mockPost.mockReset();
+		mockPatch.mockReset();
+		mockDelete.mockReset();
+		vi.resetModules();
+		const mod = await import('./+page.server');
+		actions = mod.actions;
+	});
+
+	it('addSlot calls POST /v1/week-plans/{id}/slots and returns success with slot', async () => {
+		const formData = new FormData();
+		formData.set('planId', 'plan-1');
+		formData.set('slotDate', '2026-04-01');
+		formData.set('recipeId', 'r1');
+		mockPost.mockResolvedValue({ data: { id: 's1', slotDate: '2026-04-01' }, error: undefined });
+		const result = await actions.addSlot({
+			fetch: vi.fn(),
+			request: { formData: async () => formData }
+		} as any);
+		expect(mockPost).toHaveBeenCalledWith(
+			'/v1/week-plans/{id}/slots',
+			expect.objectContaining({
+				params: { path: { id: 'plan-1' } },
+				body: { slotDate: '2026-04-01', recipeId: 'r1' }
+			})
+		);
+		expect(result.success).toBe(true);
+		expect(result.slot?.id).toBe('s1');
+	});
+
+	it('addSlot returns failure when API errors', async () => {
+		const formData = new FormData();
+		formData.set('planId', 'plan-1');
+		formData.set('slotDate', '2026-04-01');
+		formData.set('recipeId', 'r1');
+		mockPost.mockResolvedValue({ data: undefined, error: { status: 500 } });
+		const result = await actions.addSlot({
+			fetch: vi.fn(),
+			request: { formData: async () => formData }
+		} as any);
+		expect(result.success).toBe(false);
+	});
+
+	it('updateSlot calls PATCH /v1/week-plans/{planId}/slots/{slotId} and returns success', async () => {
+		const formData = new FormData();
+		formData.set('planId', 'plan-1');
+		formData.set('slotId', 's1');
+		formData.set('recipeId', 'r2');
+		mockPatch.mockResolvedValue({ data: { id: 's1' }, error: undefined });
+		const result = await actions.updateSlot({
+			fetch: vi.fn(),
+			request: { formData: async () => formData }
+		} as any);
+		expect(mockPatch).toHaveBeenCalledWith(
+			'/v1/week-plans/{planId}/slots/{slotId}',
+			expect.objectContaining({
+				params: { path: { planId: 'plan-1', slotId: 's1' } },
+				body: { recipeId: 'r2' }
+			})
+		);
+		expect(result.success).toBe(true);
+	});
+
+	it('deleteSlot calls DELETE /v1/week-plans/{planId}/slots/{slotId} and returns success', async () => {
+		const formData = new FormData();
+		formData.set('planId', 'plan-1');
+		formData.set('slotId', 's1');
+		mockDelete.mockResolvedValue({ error: undefined });
+		const result = await actions.deleteSlot({
+			fetch: vi.fn(),
+			request: { formData: async () => formData }
+		} as any);
+		expect(mockDelete).toHaveBeenCalledWith(
+			'/v1/week-plans/{planId}/slots/{slotId}',
+			expect.objectContaining({
+				params: { path: { planId: 'plan-1', slotId: 's1' } }
+			})
+		);
+		expect(result.success).toBe(true);
+	});
+});