Bump golang.org/x/crypto to v0.56.0

Fixes two high-severity DoS vulnerabilities in x/crypto/ssh
(GO-2026-6354, GO-2026-6355) reachable via the SSH and VNC clients,
flagged by GitHub Dependabot. Requires bumping the go.mod go
directive to 1.26.0.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019T8bJS8BCtY5GeSG2HBj1n

go.mod

@@ -1,6 +1,6 @@
 module github.com/andydixon/link
 
-go 1.25.12
+go 1.26.0
 
 toolchain go1.26.5
 
@@ -16,7 +16,7 @@ require (
 	github.com/ulikunitz/xz v0.5.15
 	github.com/wailsapp/wails/v2 v2.12.0
 	github.com/zalando/go-keyring v0.2.8
-	golang.org/x/crypto v0.55.0
+	golang.org/x/crypto v0.56.0
 	golang.org/x/net v0.57.0
 	golang.org/x/text v0.41.0
 	modernc.org/sqlite v1.53.0

go.sum

@@ -99,8 +99,8 @@ github.com/wailsapp/wails/v2 v2.12.0 h1:BHO/kLNWFHYjCzucxbzAYZWUjub1Tvb4cSguQozH
 github.com/wailsapp/wails/v2 v2.12.0/go.mod h1:mo1bzK1DEJrobt7YrBjgxvb5Sihb1mhAY09hppbibQg=
 github.com/zalando/go-keyring v0.2.8 h1:6sD/Ucpl7jNq10rM2pgqTs0sZ9V3qMrqfIIy5YPccHs=
 github.com/zalando/go-keyring v0.2.8/go.mod h1:tsMo+VpRq5NGyKfxoBVjCuMrG47yj8cmakZDO5QGii0=
-golang.org/x/crypto v0.55.0 h1:+KWHjbgOaAQ66dh/YlkZKHlz9ZUlq61AFirAR9ntP8M=
-golang.org/x/crypto v0.55.0/go.mod h1:uq0V9dE/fzQuJtbnL+2EhWOE63vo164FY8xqEnV9xis=
+golang.org/x/crypto v0.56.0 h1:GUh5Ii4J5jtcseSMiRqr1jXCNHoxjeV9Fmekc2oLy6Y=
+golang.org/x/crypto v0.56.0/go.mod h1:OMW5y6CY9l38uPLmxU6l6pwcXp1obtLo3e6gT7gQR2I=
 golang.org/x/mod v0.38.0 h1:MECBjubtXD7yj4HrhIUcywNaGeNVUdfVnxmPajOk4yk=
 golang.org/x/mod v0.38.0/go.mod h1:V6Xz0pq8TQ3dGqVQ1FVHuelZpAL0uNhSkk9ogYP3c40=
 golang.org/x/net v0.0.0-20210505024714-0287a6fb4125/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=