feat: add Smart Fridge shell and per-credential shell routing

Implement Samsung FridgeOS-themed shell (PLAN.md §3.3) with inventory
management, temperature controls, diagnostics, alerts, and other
appliance commands. Add per-credential shell routing so static
credentials can specify which shell to use via the `shell` config field,
passed through ssh.Permissions.Extensions.

Also extract shared ReadLine helper from bash to the shell package so
both shells can reuse terminal input handling.

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

internal/server/server.go

@@ -18,6 +18,7 @@ import (
 	"git.t-juice.club/torjus/oubliette/internal/notify"
 	"git.t-juice.club/torjus/oubliette/internal/shell"
 	"git.t-juice.club/torjus/oubliette/internal/shell/bash"
+	"git.t-juice.club/torjus/oubliette/internal/shell/fridge"
 	"git.t-juice.club/torjus/oubliette/internal/storage"
 	"golang.org/x/crypto/ssh"
 )
@@ -38,6 +39,9 @@ func New(cfg config.Config, store storage.Store, logger *slog.Logger) (*Server,
 	if err := registry.Register(bash.NewBashShell(), 1); err != nil {
 		return nil, fmt.Errorf("registering bash shell: %w", err)
 	}
+	if err := registry.Register(fridge.NewFridgeShell(), 1); err != nil {
+		return nil, fmt.Errorf("registering fridge shell: %w", err)
+	}
 
 	s := &Server{
 		cfg:           cfg,
@@ -138,10 +142,24 @@ func (s *Server) handleSession(channel ssh.Channel, requests <-chan *ssh.Request
 	defer channel.Close()
 
 	// Select a shell from the registry.
-	selectedShell, err := s.shellRegistry.Select()
-	if err != nil {
-		s.logger.Error("failed to select shell", "err", err)
-		return
+	// If the auth layer specified a shell preference, use it; otherwise random.
+	var selectedShell shell.Shell
+	if conn.Permissions != nil && conn.Permissions.Extensions["shell"] != "" {
+		shellName := conn.Permissions.Extensions["shell"]
+		sh, ok := s.shellRegistry.Get(shellName)
+		if ok {
+			selectedShell = sh
+		} else {
+			s.logger.Warn("configured shell not found, falling back to random", "shell", shellName)
+		}
+	}
+	if selectedShell == nil {
+		var err error
+		selectedShell, err = s.shellRegistry.Select()
+		if err != nil {
+			s.logger.Error("failed to select shell", "err", err)
+			return
+		}
 	}
 
 	ip := extractIP(conn.RemoteAddr())
@@ -304,7 +322,13 @@ func (s *Server) passwordCallback(conn ssh.ConnMetadata, password []byte) (*ssh.
 	}
 
 	if d.Accepted {
-		return nil, nil
+		var perms *ssh.Permissions
+		if d.Shell != "" {
+			perms = &ssh.Permissions{
+				Extensions: map[string]string{"shell": d.Shell},
+			}
+		}
+		return perms, nil
 	}
 	return nil, fmt.Errorf("rejected")
 }

internal/server/server_test.go

@@ -108,7 +108,7 @@ func TestIntegrationSSHConnect(t *testing.T) {
 			AcceptAfter:       2,
 			CredentialTTLDuration: time.Hour,
 			StaticCredentials: []config.Credential{
-				{Username: "root", Password: "toor"},
+				{Username: "root", Password: "toor", Shell: "bash"},
 			},
 		},
 		Shell: config.ShellConfig{