Rename smartrun to geniusrun throughout the codebase

Updates the Go module path, cmd/smartrund -> cmd/geniusrund, the
smartrun-dev skill, .gitignore, and every reference in docs/CLAUDE.md
to match.

backend/internal/sync/service.go

@@ -12,9 +12,9 @@ import (
 	"sync"
 	"time"
 
-	"smartrun/backend/internal/classify"
-	"smartrun/backend/internal/garmin"
-	"smartrun/backend/internal/store"
+	"geniusrun/backend/internal/classify"
+	"geniusrun/backend/internal/garmin"
+	"geniusrun/backend/internal/store"
 )
 
 // Config tunes sync behavior. Zero values fall back to sensible defaults in