Fix bugs #24-27: calendar dedup, uncomplete tasks, planning view

Bug fixes:
- #24: Deduplicate calendar events across multiple calendars using
  summary + start time as key
- #25: Change event icon from calendar to clock to avoid confusion
  with date display
- #26: Add task uncomplete functionality via ReopenTask API for
  Todoist and closed=false for Trello
- #27: Restructure planning view with sections for Scheduled (timed
  events/tasks), Today (unscheduled), Quick Add, and Upcoming (3 days)

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

1 files changed, 63 insertions, 6 deletions

diff --git a/internal/handlers/handlers.go b/internal/handlers/handlers.go
index b8fc574..c364188 100644
--- a/internal/handlers/handlers.go
+++ b/internal/handlers/handlers.go
@@ -827,21 +827,78 @@ func (h *Handler) HandleCompleteAtom(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// Return completed task HTML (stays visible with strikethrough until refresh)
+	// Return completed task HTML with uncomplete option
 	w.Header().Set("Content-Type", "text/html")
-	completedHTML := fmt.Sprintf(`<div class="task-item bg-gray-100 rounded-lg shadow-sm border-l-4 border-gray-300 opacity-60">
+	completedHTML := fmt.Sprintf(`<div class="bg-white/5 rounded-lg border border-white/5 opacity-60">
 		<div class="flex items-start gap-2 sm:gap-3 p-3 sm:p-4">
-			<input type="checkbox" checked disabled class="mt-1 h-5 w-5 rounded border-gray-300 text-green-600 cursor-not-allowed flex-shrink-0">
+			<input type="checkbox" checked
+				   hx-post="/uncomplete-atom"
+				   hx-vals='{"id": "%s", "source": "%s"}'
+				   hx-target="closest div.rounded-lg"
+				   hx-swap="outerHTML"
+				   class="mt-1 h-5 w-5 rounded bg-black/40 border-white/30 text-green-600 cursor-pointer flex-shrink-0">
 			<span class="text-lg flex-shrink-0">✓</span>
 			<div class="flex-1 min-w-0">
-				<h3 class="text-sm font-medium text-gray-400 line-through break-words">%s</h3>
-				<div class="text-xs text-green-600 mt-1">Completed</div>
+				<h3 class="text-sm font-medium text-white/40 line-through break-words">%s</h3>
+				<div class="text-xs text-green-400/70 mt-1">Completed - click to undo</div>
 			</div>
 		</div>
-	</div>`, template.HTMLEscapeString(title))
+	</div>`, template.HTMLEscapeString(id), template.HTMLEscapeString(source), template.HTMLEscapeString(title))
 	w.Write([]byte(completedHTML))
 }
 
+// HandleUncompleteAtom handles reopening a completed task
+func (h *Handler) HandleUncompleteAtom(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "Failed to parse form", http.StatusBadRequest)
+		log.Printf("Error parsing form: %v", err)
+		return
+	}
+
+	id := r.FormValue("id")
+	source := r.FormValue("source")
+
+	if id == "" || source == "" {
+		http.Error(w, "Missing id or source", http.StatusBadRequest)
+		return
+	}
+
+	var err error
+	switch source {
+	case "todoist":
+		err = h.todoistClient.ReopenTask(ctx, id)
+	case "trello":
+		// Reopen the card (closed = false)
+		updates := map[string]interface{}{
+			"closed": false,
+		}
+		err = h.trelloClient.UpdateCard(ctx, id, updates)
+	default:
+		http.Error(w, "Unknown source: "+source, http.StatusBadRequest)
+		return
+	}
+
+	if err != nil {
+		http.Error(w, "Failed to reopen task", http.StatusInternalServerError)
+		log.Printf("Error reopening atom (source=%s, id=%s): %v", source, id, err)
+		return
+	}
+
+	// Invalidate cache to force refresh
+	switch source {
+	case "todoist":
+		h.store.InvalidateCache(store.CacheKeyTodoistTasks)
+	case "trello":
+		h.store.InvalidateCache(store.CacheKeyTrelloBoards)
+	}
+
+	// Trigger refresh
+	w.Header().Set("HX-Trigger", "refresh-tasks")
+	w.WriteHeader(http.StatusOK)
+}
+
 // HandleUnifiedAdd creates a task in Todoist or a card in Trello from the Quick Add form
 func (h *Handler) HandleUnifiedAdd(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()