Sprint 6: JSON file persistence + real SSH terminal + V1 crypto/knownhosts integration

- go.mod replace directive for git.tukangketik.id/swanadiva/hostkeeper → ../../v1
- store/ package: JSON file persistence for hosts, snippets, keys, settings
  (~/Library/Application Support/hostkeeper/v2/)
- model SSH fields: Hostname, Port, Username, AuthType, Password, KeyID
- sshconn/ package: real SSH client via golang.org/x/crypto/ssh
- Terminal WS: real SSH connection with fallback to mock shell
- Dynamic host list in terminal (server-rendered JSON script tag)
- All mock data defaults removed from model packages
- Settings persist via store/settings.go

app/backend/internal/handler/terminal.go

@@ -1,39 +1,98 @@
 package handler
 
 import (
+	"bufio"
+	"encoding/json"
 	"fmt"
+	"io"
 	"log"
 	"strings"
 	"time"
 
 	"github.com/gofiber/contrib/websocket"
 	"github.com/gofiber/fiber/v2"
+	"git.tukangketik.id/swanadiva/hostkeeper/v2/internal/sshconn"
 )
 
 func Terminal(c *fiber.Ctx) error {
+	hosts := hostStore.All()
+	type hostItem struct {
+		ID   string `json:"id"`
+		Name string `json:"name"`
+		IP   string `json:"ip"`
+	}
+	var available []hostItem
+	for _, h := range hosts {
+		if h.Status == "active" {
+			available = append(available, hostItem{h.ID, h.Name, h.IP})
+		}
+	}
+	hostsJSON, _ := json.Marshal(available)
 	return c.Render("terminal", fiber.Map{
-		"View":     "terminal",
-		"Title":    "Terminal",
-		"NavItems": navItems,
+		"View":      "terminal",
+		"Title":     "Terminal",
+		"NavItems":  navItems,
+		"Hosts":     available,
+		"HostsJSON": string(hostsJSON),
 	})
 }
 
-var hostList = []struct {
-	ID   string
-	Name string
-	IP   string
-}{
-	{"h1", "api-prod-01", "10.0.1.15"},
-	{"h2", "db-primary-01", "10.0.2.5"},
-	{"h6", "monitor-01", "10.0.0.5"},
-	{"h7", "worker-pool-01", "10.0.4.50"},
+func TerminalWS(c *websocket.Conn) {
+	hostID := c.Params("host", "unknown")
+	log.Printf("WS connected: host=%s", hostID)
+
+	host, found := hostStore.Get(hostID)
+	if !found || host.Hostname == "" {
+		mockTerminal(c, hostID)
+		return
+	}
+
+	client, err := sshconn.Dial(host)
+	if err != nil {
+		log.Printf("SSH failed for %s: %v, falling back to mock", hostID, err)
+		mockTerminal(c, hostID)
+		return
+	}
+	defer client.Close()
+
+	welcome := fmt.Sprintf("\x1b[1;32mConnected to %s (%s)\x1b[0m\r\n", host.Name, host.IP)
+	c.WriteMessage(websocket.TextMessage, []byte(welcome))
+
+	stdinR, stdinW := io.Pipe()
+	stdoutR, stdoutW := io.Pipe()
+
+	go func() {
+		scanner := bufio.NewScanner(stdoutR)
+		for scanner.Scan() {
+			c.WriteMessage(websocket.TextMessage, []byte(scanner.Text()+"\r\n"))
+		}
+	}()
+
+	go func() {
+		defer stdinW.Close()
+		for {
+			_, msg, err := c.ReadMessage()
+			if err != nil {
+				return
+			}
+			input := string(msg)
+			if input == "\x03" {
+				client.Close()
+				return
+			}
+			stdinW.Write([]byte(input))
+		}
+	}()
+
+	if err := client.Shell(stdinR, stdoutW, stdoutW, 24, 80); err != nil {
+		log.Printf("SSH session ended: %v", err)
+	}
+
+	log.Printf("WS disconnected: host=%s", hostID)
 }
 
-func TerminalWS(c *websocket.Conn) {
-	host := c.Params("host", "unknown")
-	log.Printf("WS connected: host=%s", host)
-
-	welcome := fmt.Sprintf("\x1b[1;32mWelcome to %s\x1b[0m\r\n\x1b[2mConnected at %s\x1b[0m\r\n\r\n", host, time.Now().Format(time.RFC822))
+func mockTerminal(c *websocket.Conn, host string) {
+	welcome := fmt.Sprintf("\x1b[1;33m%s (mock mode)\x1b[0m\r\n\x1b[2mConnected at %s\x1b[0m\r\n\r\n", host, time.Now().Format(time.RFC822))
 	c.WriteMessage(websocket.TextMessage, []byte(welcome))
 
 	prompt := fmt.Sprintf("\x1b[1;34m%s:~$\x1b[0m ", host)
@@ -68,19 +127,15 @@ func TerminalWS(c *websocket.Conn) {
 			}
 		}
 	}
-	log.Printf("WS disconnected: host=%s", host)
+	log.Printf("Mock WS disconnected: host=%s", host)
 }
 
 func handleCommand(cmd, host string, cwd *string) string {
 	cmd = strings.TrimSpace(cmd)
-	if cmd == "" {
-		return ""
-	}
+	if cmd == "" { return "" }
 
 	parts := strings.Fields(cmd)
-	if len(parts) == 0 {
-		return ""
-	}
+	if len(parts) == 0 { return "" }
 
 	switch parts[0] {
 	case "clear":
@@ -108,11 +163,7 @@ func handleCommand(cmd, host string, cwd *string) string {
 		}
 		return "total 0\r\n"
 	case "cd":
-		if len(parts) > 1 {
-			*cwd = parts[1]
-		} else {
-			*cwd = "~"
-		}
+		if len(parts) > 1 { *cwd = parts[1] } else { *cwd = "~" }
 		return ""
 	case "cat":
 		if len(parts) > 1 {