Require secret at the commit that drops go-bip39 (closes #70)

sneak/secret now carries its own copy of go-bip39
(sneak/secret#130), so requiring it at that
commit, ef0ae90, lets go mod tidy drop go-bip39 from go.sum. Earlier,
secret renamed its module to sneak.berlin/go/secret
(sneak/secret#43), so the requirement, the
two imports of its bip85 package and the README sentence naming that
package move to the new path. The bip85 functions keyfunc calls are
unchanged, and no other requirement moves.

Model: opus-5-5
Co-authored-by: clawbot <sneak+clawbot@sneak.cloud>

go.sum

@@ -4,8 +4,6 @@ filippo.io/age v1.3.2 h1:r6RSZLFSMm6rzKepZ7ZAYkKCu14f3/Me8c7uKYh7C8c=
 filippo.io/age v1.3.2/go.mod h1:TH/Yr2sSRhCKbaH4XPxpUV0Us8Gv6txYUpiZQWz8Evk=
 filippo.io/hpke v0.4.0 h1:p575VVQ6ted4pL+it6M00V/f2qTZITO0zgmdKCkd5+A=
 filippo.io/hpke v0.4.0/go.mod h1:EmAN849/P3qdeK+PCMkDpDm83vRHM5cDipBJ8xbQLVY=
-git.eeqj.de/sneak/secret v0.0.0-20260810132333-41cea400a7fd h1:6YFV6horz2wDFPWWhour8qx8gLGyO0qoplwEeOuQ2J4=
-git.eeqj.de/sneak/secret v0.0.0-20260810132333-41cea400a7fd/go.mod h1:gKCcMZvlBOqusn/BxR8IyFmSJQr6R4vvjJ926iNpOSI=
 github.com/btcsuite/btcd v0.25.0 h1:JPbjwvHGpSywBRuorFFqTjaVP4y6Qw69XJ1nQ6MyWJM=
 github.com/btcsuite/btcd v0.25.0/go.mod h1:qbPE+pEiR9643E1s1xu57awsRhlCIm1ZIi6FfeRA4KE=
 github.com/btcsuite/btcd/btcec/v2 v2.5.0 h1:KioMXOWa76b86sTZZOmbzv/ldaQCmB8KFAyn5PbB8E8=
@@ -30,8 +28,6 @@ github.com/spf13/pflag v1.0.9 h1:9exaQaMOCwffKiiiYk6/BndUBv+iRViNW+4lEMi0PvY=
 github.com/spf13/pflag v1.0.9/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/stretchr/testify v1.12.1 h1:EuwCh5fleGS7H32xRwO3wRGT7DxrDhLAT6FF8MpWDWE=
 github.com/stretchr/testify v1.12.1/go.mod h1:MDEgiDPPsNp5cuIrHPPCyornHKgEVbtFUmoNlxoYthg=
-github.com/tyler-smith/go-bip39 v1.1.0 h1:5eUemwrMargf3BSLRRCalXT93Ns6pQJIjYQN2nyfOP8=
-github.com/tyler-smith/go-bip39 v1.1.0/go.mod h1:gUYDtqQw1JS3ZJ8UWVcGTGqqr6YIN3CWg+kkNaLt55U=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
 go.yaml.in/yaml/v3 v3.0.5 h1:N6y/pJk8buWs9NY5ERU2HSMfm+IuD/OtfdAnq6kESPw=
 go.yaml.in/yaml/v3 v3.0.5/go.mod h1:HVTZu1O7/Vkt2N+BFy8Zza+lnLsABggaTM2ZpNIGuKg=
@@ -42,3 +38,5 @@ golang.org/x/sys v0.48.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=
 golang.org/x/term v0.46.0 h1:3+OXuTbaKDgwk8jTi3aSLHRlmWqHEUDUtxnbFigO4YE=
 golang.org/x/term v0.46.0/go.mod h1:+K02xbkittuwc0Am4abfA3Fc+XRGXkvBXNO88NCXPoc=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+sneak.berlin/go/secret v0.0.0-20261007105610-ef0ae90768c8 h1:Bd2bUsRCN8xhcrpH3LpJqHxR2QffeOuF5z76iP4BFnw=
+sneak.berlin/go/secret v0.0.0-20261007105610-ef0ae90768c8/go.mod h1:uVx9ZuE7ZMIOBY2B1ElXCs97CTsEfuham3NQRdLj5lI=