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

internal/packages/packages.go

@@ -16,7 +16,7 @@ const collectTimeout = 2 * time.Minute
 //
 // The format strings below are raw string literals on purpose. The "\t" and
 // "\n" reach dpkg-query and rpm as two characters each, and those tools do the
-// interpreting themselves — Go must not consume the escapes first.
+// interpreting themselves - Go must not consume the escapes first.
 func Collect() (OSRelease, []Package, error) {
 	if runtime.GOOS != "linux" {
 		return OSRelease{}, nil, fmt.Errorf("package collection is linux-only, got %s", runtime.GOOS)

internal/packages/parse.go

@@ -9,7 +9,7 @@ import (
 )
 
 // Package is one installed package as the distribution reports it. Version is
-// the distribution's own version string, verbatim — never normalised, because
+// the distribution's own version string, verbatim - never normalised, because
 // the advisory feeds are keyed on exactly this form.
 type Package struct {
 	Name       string
@@ -29,7 +29,7 @@ type Package struct {
 //
 // The fifth column is why "rc" packages do not appear. dpkg-query -W lists
 // every package dpkg knows about, including ones removed with their config
-// files left behind — a host that has upgraded its kernel a dozen times reports
+// files left behind - a host that has upgraded its kernel a dozen times reports
 // a dozen old linux-modules versions that are not on disk, and the oldest of
 // them sorts first and reads as the installed version. Only "installed" is
 // installed. An empty status means dpkg did not understand the field, in which
@@ -143,7 +143,7 @@ func splitAPK(s string) (name, version string) {
 //
 // It sorts first: the ordering of dpkg or rpm output is not guaranteed stable,
 // and an ordering-sensitive hash would resend the full ~150KB list every hour
-// for no reason — a cost visible only as traffic.
+// for no reason - a cost visible only as traffic.
 func Hash(pkgs []Package) string {
 	lines := make([]string, 0, len(pkgs))
 	for _, p := range pkgs {