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/store/activities.go

@@ -6,7 +6,7 @@ import (
 	"fmt"
 )
 
-// Activity is smartrun's persisted view of a Garmin activity. Field mapping
+// Activity is geniusrun's persisted view of a Garmin activity. Field mapping
 // from the Garmin/MCP response happens in internal/sync, not here, so this
 // package stays independent of internal/garmin.
 //

backend/internal/store/db.go

@@ -1,4 +1,4 @@
-// Package store is smartrun's SQLite persistence layer: activities, laps,
+// Package store is geniusrun's SQLite persistence layer: activities, laps,
 // per-second samples, workout kind rule config, and classification history.
 package store
 
@@ -15,7 +15,7 @@ import (
 //go:embed migrations/*.sql
 var migrationsFS embed.FS
 
-// DB wraps a *sql.DB opened against a smartrun SQLite database file, with
+// DB wraps a *sql.DB opened against a geniusrun SQLite database file, with
 // migrations already applied.
 type DB struct {
 	*sql.DB

backend/internal/store/migrations/0009_backfill_horizon.sql

@@ -1,5 +1,5 @@
 -- Backfill horizon used to be a startup-time env var
--- (SMARTRUN_BACKFILL_HORIZON_DAYS) with no UI at all -- exactly the kind of
+-- (GENIUSRUN_BACKFILL_HORIZON_DAYS) with no UI at all -- exactly the kind of
 -- "tunable analysis-engine parameter" this profile table exists for.
 -- Default matches the old env var's default (3 years) so existing
 -- deployments keep their current behavior until the user changes it.

backend/internal/store/store_test.go

@@ -8,7 +8,7 @@ import (
 
 func openTestDB(t *testing.T) *DB {
 	t.Helper()
-	path := filepath.Join(t.TempDir(), "smartrun_test.db")
+	path := filepath.Join(t.TempDir(), "geniusrun_test.db")
 	db, err := Open(path)
 	if err != nil {
 		t.Fatalf("Open: %v", err)
@@ -20,7 +20,7 @@ func openTestDB(t *testing.T) *DB {
 func f(v float64) *float64 { return &v }
 
 func TestMigrateIsIdempotent(t *testing.T) {
-	path := filepath.Join(t.TempDir(), "smartrun_test.db")
+	path := filepath.Join(t.TempDir(), "geniusrun_test.db")
 	db1, err := Open(path)
 	if err != nil {
 		t.Fatalf("first Open: %v", err)