Rename module to sneak.berlin/go/x and rework bip39wordlist

Move to Go 1.26, embed the wordlist from english.txt, add
ValidateWordlist, NormalizeWordlist, and GenerateMnemonic with tests,
and remove the old root-level CLI that used the previous module path.

go.mod

@@ -1,10 +1,19 @@
-module sneak.berlin/x
+module sneak.berlin/go/x
 
-go 1.15
+go 1.26.0
 
 require (
-	github.com/mitchellh/go-homedir v1.1.0
-	github.com/spf13/cobra v1.0.0
-	github.com/spf13/viper v1.7.1
-	github.com/stretchr/testify v1.3.0
+	github.com/kavfixnel/words v1.0.0
+	github.com/spf13/cobra v1.10.2
+	github.com/stretchr/testify v1.12.1
+	github.com/tyler-smith/go-bip39 v1.1.0
+	golang.org/x/crypto v0.58.0
+)
+
+require (
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/spf13/pflag v1.0.9 // indirect
+	go.yaml.in/yaml/v3 v3.0.5 // indirect
+	golang.org/x/sys v0.49.0 // indirect
+	golang.org/x/text v0.43.0 // indirect
 )