feat: native task management + Todoist migration

Adds doot-owned task storage (native_tasks table) so tasks can be
managed without Todoist. CompleteTask for 'doot' source just updates
the DB — no external API call, no token dependency.

Migration path:
  POST /settings/import-from-todoist  — copies Todoist cache → native_tasks
  Then remove TODOIST_TOKEN from .env to disable Todoist

Changes:
- migration 020: native_tasks table
- store: GetNativeTasks, GetNativeTasksByDateRange, GetUndatedNativeTasks,
  CreateNativeTask, CompleteNativeTask, UncompleteNativeTask,
  UpdateNativeTask, ImportFromTodoist
- timeline: native tasks appear as source="doot" (teal)
- handleAtomToggle: "doot" case — no external API needed
- HandleWidgetComplete: method on Handler, handles "doot" natively
- HandleUnifiedAdd: "doot" source creates in native_tasks
- widget: "doot" tasks are completable, teal color indicator

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

1 files changed, 22 insertions, 15 deletions

diff --git a/internal/handlers/widget.go b/internal/handlers/widget.go
index 00efc75..360ccc5 100644
--- a/internal/handlers/widget.go
+++ b/internal/handlers/widget.go
@@ -6,7 +6,6 @@ import (
 	"strings"
 	"time"
 
-	"task-dashboard/internal/api"
 	"task-dashboard/internal/config"
 	"task-dashboard/internal/models"
 )
@@ -48,7 +47,7 @@ func TimelineItemToWidgetItem(item models.TimelineItem) models.WidgetItem {
 		// not completable via widget API
 	default:
 		wi.Type = "task"
-		wi.Completable = item.Source == "todoist"
+		wi.Completable = item.Source == "todoist" || item.Source == "doot"
 	}
 
 	// Only populate Start/End for items with a real time (non-all-day, non-zero)
@@ -102,26 +101,34 @@ type widgetCompleteRequest struct {
 	Source string `json:"source"`
 }
 
-// HandleWidgetComplete proxies a task completion to the source API.
-func HandleWidgetComplete(todoistClient api.TodoistAPI) http.HandlerFunc {
-	return func(w http.ResponseWriter, r *http.Request) {
-		var req widgetCompleteRequest
-		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-			http.Error(w, "bad request", http.StatusBadRequest)
-			return
-		}
-		if req.Source != "todoist" {
-			http.Error(w, "source not completable", http.StatusBadRequest)
+// HandleWidgetComplete proxies a task completion to the source API or native store.
+func (h *Handler) HandleWidgetComplete(w http.ResponseWriter, r *http.Request) {
+	var req widgetCompleteRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "bad request", http.StatusBadRequest)
+		return
+	}
+
+	switch req.Source {
+	case "doot":
+		if err := h.store.CompleteNativeTask(req.ID); err != nil {
+			http.Error(w, "failed to complete task", http.StatusInternalServerError)
 			return
 		}
-		if todoistClient == nil {
+		_ = h.store.SaveCompletedTask("doot", req.ID, "", nil)
+	case "todoist":
+		if h.todoistClient == nil {
 			http.Error(w, "todoist not configured", http.StatusServiceUnavailable)
 			return
 		}
-		if err := todoistClient.CompleteTask(r.Context(), req.ID); err != nil {
+		if err := h.todoistClient.CompleteTask(r.Context(), req.ID); err != nil {
 			http.Error(w, "failed to complete task", http.StatusInternalServerError)
 			return
 		}
-		w.WriteHeader(http.StatusOK)
+	default:
+		http.Error(w, "source not completable", http.StatusBadRequest)
+		return
 	}
+
+	w.WriteHeader(http.StatusOK)
 }