Surface budget_status on GET /api/widget when tracked tasks exist

Wires ComputeBudgetPeriod together with availability blocks, tracked
project/label sets, calendar events, and native tasks into a new
computeBudgetStatus helper on *Handler. HandleWidgetGet now populates
WidgetResponse.BudgetStatus with today/week periods, but only when at
least one incomplete budget-tracked task exists in the rolling week
window -- otherwise the field is omitted entirely so unconfigured users
see no new UI. Errors are logged and swallowed, matching the existing
resilience pattern for this widget endpoint.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PQaPGQVSfmKUiHXB87qRTC

3 files changed, 118 insertions, 4 deletions

diff --git a/internal/handlers/widget.go b/internal/handlers/widget.go
index 05c0bdb..bff7dd7 100644
--- a/internal/handlers/widget.go
+++ b/internal/handlers/widget.go
@@ -3,6 +3,7 @@ package handlers
 import (
 	"encoding/json"
 	"errors"
+	"log"
 	"net/http"
 	"strings"
 	"time"
@@ -126,15 +127,73 @@ func (h *Handler) HandleWidgetGet(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	budgetStatus, err := h.computeBudgetStatus(now)
+	if err != nil {
+		log.Printf("Warning: failed to compute budget status: %v", err)
+	}
+
 	resp := models.WidgetResponse{
-		Now:   now,
-		Items: widgetItems,
+		Now:          now,
+		Items:        widgetItems,
+		BudgetStatus: budgetStatus,
 	}
 
 	w.Header().Set("Content-Type", "application/json")
 	_ = json.NewEncoder(w).Encode(resp)
 }
 
+// computeBudgetStatus returns budget status for "today" and a rolling
+// 7-day "week" window starting today, or nil if no budget-tracked task
+// falls in the week window (per the spec: the field is absent unless
+// budget-tracked tasks exist, so an unconfigured user sees no new UI).
+func (h *Handler) computeBudgetStatus(now time.Time) (*models.BudgetStatus, error) {
+	tz := config.GetDisplayTimezone()
+	todayStart := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, tz)
+	todayEnd := todayStart.Add(24 * time.Hour)
+	weekEnd := todayStart.AddDate(0, 0, 7)
+
+	blocks, err := h.store.GetAvailabilityBlocks()
+	if err != nil {
+		return nil, err
+	}
+	trackedProjects, err := h.store.GetBudgetTrackedProjectIDs()
+	if err != nil {
+		return nil, err
+	}
+	trackedLabels, err := h.store.GetBudgetTrackedLabelNames()
+	if err != nil {
+		return nil, err
+	}
+	events, err := h.store.GetCalendarEventsByDateRange(todayStart, weekEnd)
+	if err != nil {
+		return nil, err
+	}
+	overdue, err := h.store.GetOverdueNativeTasks(todayStart)
+	if err != nil {
+		return nil, err
+	}
+	weekTasks, err := h.store.GetNativeTasksByDateRange(todayStart, weekEnd)
+	if err != nil {
+		return nil, err
+	}
+	allTasks := append(append([]models.Task{}, overdue...), weekTasks...)
+
+	hasTracked := false
+	for _, task := range allTasks {
+		if isBudgetTracked(task, trackedProjects, trackedLabels) && !task.Completed {
+			hasTracked = true
+			break
+		}
+	}
+	if !hasTracked {
+		return nil, nil
+	}
+
+	today := ComputeBudgetPeriod(blocks, events, allTasks, trackedProjects, trackedLabels, todayStart, todayEnd)
+	week := ComputeBudgetPeriod(blocks, events, allTasks, trackedProjects, trackedLabels, todayStart, weekEnd)
+	return &models.BudgetStatus{Today: today, Week: week}, nil
+}
+
 type widgetCompleteRequest struct {
 	ID     string `json:"id"`
 	Source string `json:"source"`
diff --git a/internal/handlers/widget_test.go b/internal/handlers/widget_test.go
index f934dba..a638eca 100644
--- a/internal/handlers/widget_test.go
+++ b/internal/handlers/widget_test.go
@@ -1214,3 +1214,57 @@ func TestTimelineItemToWidgetItem_NoProject_NilProjectColor(t *testing.T) {
 	}
 }
 
+func TestHandleWidgetGet_NoBudgetTrackedTasks_OmitsBudgetStatus(t *testing.T) {
+	db, cleanup := setupTestDB(t)
+	defer cleanup()
+	h := &Handler{store: db}
+
+	req := httptest.NewRequest("GET", "/api/widget", nil)
+	w := httptest.NewRecorder()
+	h.HandleWidgetGet(w, req)
+
+	var resp models.WidgetResponse
+	if err := json.NewDecoder(w.Body).Decode(&resp); err != nil {
+		t.Fatal(err)
+	}
+	if resp.BudgetStatus != nil {
+		t.Errorf("expected nil BudgetStatus with no tracked tasks, got %+v", resp.BudgetStatus)
+	}
+}
+
+func TestHandleWidgetGet_BudgetTrackedTaskDueToday_IncludesBudgetStatus(t *testing.T) {
+	db, cleanup := setupTestDB(t)
+	defer cleanup()
+	h := &Handler{store: db}
+
+	project, err := h.store.CreateProject("Tracked", "#111111")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := h.store.SetProjectBudgetTracked(project.ID, true); err != nil {
+		t.Fatal(err)
+	}
+	due := time.Now()
+	if err := h.store.CreateNativeTask(models.Task{ID: "t-tracked", Content: "Tracked task", ProjectID: project.ID, DueDate: &due, EstimatedMinutes: 45}); err != nil {
+		t.Fatal(err)
+	}
+
+	req := httptest.NewRequest("GET", "/api/widget", nil)
+	w := httptest.NewRecorder()
+	h.HandleWidgetGet(w, req)
+
+	var resp models.WidgetResponse
+	if err := json.NewDecoder(w.Body).Decode(&resp); err != nil {
+		t.Fatal(err)
+	}
+	if resp.BudgetStatus == nil {
+		t.Fatal("expected non-nil BudgetStatus")
+	}
+	if resp.BudgetStatus.Today.ScheduledMinutes != 45 {
+		t.Errorf("Today.ScheduledMinutes = %d, want 45", resp.BudgetStatus.Today.ScheduledMinutes)
+	}
+	if resp.BudgetStatus.Week.ScheduledMinutes != 45 {
+		t.Errorf("Week.ScheduledMinutes = %d, want 45", resp.BudgetStatus.Week.ScheduledMinutes)
+	}
+}
+
diff --git a/internal/models/widget.go b/internal/models/widget.go
index da13008..bf148fd 100644
--- a/internal/models/widget.go
+++ b/internal/models/widget.go
@@ -23,6 +23,7 @@ type WidgetItem struct {
 
 // WidgetResponse is the full /api/widget response body.
 type WidgetResponse struct {
-	Now   time.Time    `json:"now"`
-	Items []WidgetItem `json:"items"`
+	Now          time.Time     `json:"now"`
+	Items        []WidgetItem  `json:"items"`
+	BudgetStatus *BudgetStatus `json:"budget_status,omitempty"`
 }