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, 4 insertions, 1 deletions

diff --git a/cmd/dashboard/main.go b/cmd/dashboard/main.go
index 92a149b..c154d9b 100644
--- a/cmd/dashboard/main.go
+++ b/cmd/dashboard/main.go
@@ -342,6 +342,9 @@ func main() {
 		r.Post("/passkeys/register/finish", authHandlers.HandlePasskeyRegisterFinish)
 		r.Delete("/passkeys/{id}", authHandlers.HandleDeletePasskey)
 
+		// Native task management
+		r.Post("/settings/import-from-todoist", h.HandleImportFromTodoist)
+
 		// Settings
 		r.Get("/settings", h.HandleSettingsPage)
 		r.Post("/settings/sync", h.HandleSyncSources)
@@ -362,7 +365,7 @@ func main() {
 			return handlers.WidgetAuthMiddleware(cfg.WidgetToken, next)
 		}
 		r.With(widgetAuth).Get("/api/widget", h.HandleWidgetGet)
-		r.With(widgetAuth).Post("/api/widget/complete", handlers.HandleWidgetComplete(todoistClient))
+		r.With(widgetAuth).Post("/api/widget/complete", h.HandleWidgetComplete)
 	} else {
 		log.Println("WIDGET_TOKEN not set — /api/widget disabled")
 	}