feat: implement SSH honeypot server with auth and config

Add core SSH server with password authentication, per-IP failure
tracking, credential memory with TTL, and static credential support.
Includes TOML config loading with validation, Ed25519 host key
auto-generation, and a Nix package output.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

go.mod

@@ -1,3 +1,9 @@
 module git.t-juice.club/torjus/oubliette
 
 go 1.25.5
+
+require (
+	github.com/BurntSushi/toml v1.6.0 // indirect
+	golang.org/x/crypto v0.48.0 // indirect
+	golang.org/x/sys v0.41.0 // indirect
+)