chore: replace em dashes with hyphens, add no-em-dash rule to CLAUDE.md

backup/restore.go

@@ -72,7 +72,7 @@ func (o RestoreOptions) warn(format string, args ...any) {
 // The order is fixed and every check that can refuse does so before the first
 // write: format, checksums (done by Open), key policy, then target inspection.
 // A restore that has begun writing and then fails leaves a partial database
-// which the next run refuses to touch, which is correct — the alternative is a
+// which the next run refuses to touch, which is correct - the alternative is a
 // silent merge, and merging two control planes reconciles nothing.
 func Restore(ctx context.Context, opt RestoreOptions) (RestoreResult, error) {
 	m := opt.Archive.Manifest()
@@ -302,14 +302,14 @@ func splitBSON(raw []byte) (bson.Raw, []byte, error) {
 // The specs are handed to the createIndexes command exactly as the source
 // server reported them, rather than reconstructed into a mongo.IndexModel from
 // a hand-picked set of options. Reconstruction dropped every option nobody had
-// thought to pick — partialFilterExpression above all, which this codebase
+// thought to pick - partialFilterExpression above all, which this codebase
 // relies on for partial unique indexes, and which replayed as a full unique
 // index fails on any real database. It also lost compound key order, which is
 // significant.
 //
 // A unique index that will not build means the restored data violates it, and
-// the unique indexes here — (instance_id, email), instance slug, settings
-// instance, the ESO token hash — are tenant-isolation properties rather than
+// the unique indexes here - (instance_id, email), instance slug, settings
+// instance, the ESO token hash - are tenant-isolation properties rather than
 // optimisations. That aborts. A non-unique index failing is a performance
 // problem and warns.
 func replayIndexes(ctx context.Context, opt RestoreOptions, coll *mongo.Collection, name string) (int, error) {