Update dependencies to current releases (closes #19)

Every direct dependency moves to its current release, golang.org/x/crypto first: keyfunc ssh to serves keys through its ssh/agent package, which has had security fixes since the pinned 2025-05 version. go.mod and go.sum only; no code changed and the SSH, age and child mnemonic test vectors pass unedited, so no derived key moves.

Model: opus-4-8 (implementation); fable-5-1 (summary)

go.mod

@@ -1,27 +1,27 @@
 module git.eeqj.de/sneak/keyfunc
 
-go 1.26
+go 1.26.0
 
 require (
-	filippo.io/age v1.2.1
+	filippo.io/age v1.3.2
 	git.eeqj.de/sneak/secret v0.0.0-20260810132333-41cea400a7fd
-	github.com/btcsuite/btcd v0.24.2
-	github.com/btcsuite/btcd/btcutil v1.1.6
-	github.com/spf13/cobra v1.9.1
-	github.com/stretchr/testify v1.8.4
+	github.com/btcsuite/btcd v0.25.0
+	github.com/btcsuite/btcd/btcutil v1.2.0
+	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 v0.38.0
-	golang.org/x/term v0.32.0
+	golang.org/x/crypto v0.57.0
+	golang.org/x/term v0.46.0
 )
 
 require (
-	github.com/btcsuite/btcd/btcec/v2 v2.1.3 // indirect
-	github.com/btcsuite/btcd/chaincfg/chainhash v1.1.0 // indirect
-	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1 // indirect
+	filippo.io/hpke v0.4.0 // indirect
+	github.com/btcsuite/btcd/btcec/v2 v2.5.0 // indirect
+	github.com/btcsuite/btcd/chaincfg/chainhash v1.2.0 // indirect
+	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.4.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
-	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/spf13/pflag v1.0.6 // indirect
-	golang.org/x/sys v0.33.0 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
+	github.com/kcalvinalvin/anet v0.0.0-20251112173137-d8ddc1f6dbee // indirect
+	github.com/spf13/pflag v1.0.9 // indirect
+	go.yaml.in/yaml/v3 v3.0.5 // indirect
+	golang.org/x/sys v0.48.0 // indirect
 )