Fix timeline calendar view and shopping UI bugs (#56, #65-73)

- #56: Add overflow-hidden to card/panel classes to prevent content overflow
- #65: Fix Google Tasks not showing by including tasks without due dates
- #66: Add no-cache headers to prevent stale template responses
- #67: Increase dropdown z-index to 100 for proper layering
- #69: Implement calendar-style Today section with hourly grid (6am-10pm),
       duration-based event heights, and compact overdue/all-day section
- #70: Only reset shopping-mode form on successful submission
- #71: Remove checkboxes from shopping tab (only show in shopping mode)
- #72: Add inline add-item input at end of each store section
- #73: Add Grouped/Flat view toggle for shopping list

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

3 files changed, 36 insertions, 7 deletions

diff --git a/internal/handlers/handlers.go b/internal/handlers/handlers.go
index 0e5edcc..bba12ad 100644
--- a/internal/handlers/handlers.go
+++ b/internal/handlers/handlers.go
@@ -1230,7 +1230,11 @@ func mealTypeOrder(mealType string) int {
 func (h *Handler) HandleTabShopping(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
 	stores := h.aggregateShoppingLists(ctx)
-	HTMLResponse(w, h.templates, "shopping-tab", struct{ Stores []models.ShoppingStore }{stores})
+	grouped := r.URL.Query().Get("grouped") != "false" // Default to grouped
+	HTMLResponse(w, h.templates, "shopping-tab", struct {
+		Stores  []models.ShoppingStore
+		Grouped bool
+	}{stores, grouped})
 }
 
 // HandleShoppingQuickAdd adds a user shopping item
@@ -1285,7 +1289,10 @@ func (h *Handler) HandleShoppingQuickAdd(w http.ResponseWriter, r *http.Request)
 	}
 
 	// Return refreshed shopping tab
-	HTMLResponse(w, h.templates, "shopping-tab", struct{ Stores []models.ShoppingStore }{allStores})
+	HTMLResponse(w, h.templates, "shopping-tab", struct {
+		Stores  []models.ShoppingStore
+		Grouped bool
+	}{allStores, true})
 }
 
 // HandleShoppingToggle toggles a shopping item's checked state
@@ -1323,7 +1330,10 @@ func (h *Handler) HandleShoppingToggle(w http.ResponseWriter, r *http.Request) {
 
 	// Return refreshed shopping tab
 	stores := h.aggregateShoppingLists(r.Context())
-	HTMLResponse(w, h.templates, "shopping-tab", struct{ Stores []models.ShoppingStore }{stores})
+	HTMLResponse(w, h.templates, "shopping-tab", struct {
+		Stores  []models.ShoppingStore
+		Grouped bool
+	}{stores, true})
 }
 
 // HandleShoppingMode renders the focused shopping mode for a single store
diff --git a/internal/handlers/response.go b/internal/handlers/response.go
index 9a7ab45..34d4491 100644
--- a/internal/handlers/response.go
+++ b/internal/handlers/response.go
@@ -7,9 +7,17 @@ import (
 	"net/http"
 )
 
+// noCacheHeaders sets headers to prevent browser caching
+func noCacheHeaders(w http.ResponseWriter) {
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	w.Header().Set("Pragma", "no-cache")
+	w.Header().Set("Expires", "0")
+}
+
 // JSONResponse writes data as JSON with appropriate headers
 func JSONResponse(w http.ResponseWriter, data interface{}) {
 	w.Header().Set("Content-Type", "application/json")
+	noCacheHeaders(w)
 	_ = json.NewEncoder(w).Encode(data)
 }
 
@@ -23,6 +31,8 @@ func JSONError(w http.ResponseWriter, status int, msg string, err error) {
 
 // HTMLResponse renders an HTML template
 func HTMLResponse(w http.ResponseWriter, tmpl *template.Template, name string, data interface{}) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	noCacheHeaders(w)
 	if err := tmpl.ExecuteTemplate(w, name, data); err != nil {
 		http.Error(w, "Failed to render template", http.StatusInternalServerError)
 		log.Printf("Error rendering template %s: %v", name, err)
diff --git a/internal/handlers/timeline_logic.go b/internal/handlers/timeline_logic.go
index 5ea44b5..7a85393 100644
--- a/internal/handlers/timeline_logic.go
+++ b/internal/handlers/timeline_logic.go
@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"context"
+	"log"
 	"sort"
 	"strings"
 	"time"
@@ -130,7 +131,9 @@ func BuildTimeline(ctx context.Context, s *store.Store, calendarClient api.Googl
 	// 4. Fetch Events
 	if calendarClient != nil {
 		events, err := calendarClient.GetEventsByDateRange(ctx, start, end)
-		if err == nil {
+		if err != nil {
+			log.Printf("Warning: failed to fetch calendar events: %v", err)
+		} else {
 			for _, event := range events {
 				endTime := event.End
 				item := models.TimelineItem{
@@ -142,7 +145,7 @@ func BuildTimeline(ctx context.Context, s *store.Store, calendarClient api.Googl
 					Description:  event.Description,
 					URL:          event.HTMLLink,
 					OriginalItem: event,
-					IsCompleted:  false, // Events don't have completion status
+					IsCompleted:  false,
 					Source:       "calendar",
 				}
 				item.ComputeDaySection(now)
@@ -154,9 +157,13 @@ func BuildTimeline(ctx context.Context, s *store.Store, calendarClient api.Googl
 	// 5. Fetch Google Tasks
 	if tasksClient != nil {
 		gTasks, err := tasksClient.GetTasksByDateRange(ctx, start, end)
-		if err == nil {
+		if err != nil {
+			log.Printf("Warning: failed to fetch Google Tasks: %v", err)
+		} else {
+			log.Printf("Google Tasks: fetched %d tasks in date range", len(gTasks))
 			for _, gTask := range gTasks {
-				taskTime := start // Default to start of range if no due date
+				// Tasks without due date are placed in today section
+				taskTime := now
 				if gTask.DueDate != nil {
 					taskTime = *gTask.DueDate
 				}
@@ -176,6 +183,8 @@ func BuildTimeline(ctx context.Context, s *store.Store, calendarClient api.Googl
 				items = append(items, item)
 			}
 		}
+	} else {
+		log.Printf("Google Tasks client not configured")
 	}
 
 	// Sort items by Time