🔧 fix(release,ssh): 修复 SSH 误判连接成功并纠正 DMG 打包结构

- SSH 缓存 key 纳入认证指纹（password/keyPath），避免改错凭证仍复用旧连接/端口转发
- MySQL/MariaDB/Doris：SSH 隧道建立失败直接返回错误，不再回退直连导致测试误判成功
- 新增最小单测覆盖 SSH cache key 与 UseSSH 异常路径
- build-release.sh：create-dmg 使用 staging 目录作为 source，避免 DMG 根目录变成 Contents
- refs #213

internal/ssh/ssh_cache_key_test.go

@@ -0,0 +1,46 @@
+package ssh
+
+import (
+	"testing"
+
+	"GoNavi-Wails/internal/connection"
+)
+
+func TestNewSSHClientCacheKey_DiffPassword(t *testing.T) {
+	a := newSSHClientCacheKey(connection.SSHConfig{
+		Host:     "127.0.0.1",
+		Port:     22,
+		User:     "root",
+		Password: "a",
+	})
+	b := newSSHClientCacheKey(connection.SSHConfig{
+		Host:     "127.0.0.1",
+		Port:     22,
+		User:     "root",
+		Password: "b",
+	})
+	if a == b {
+		t.Fatalf("expected different cache key when password differs")
+	}
+	if a.host != b.host || a.port != b.port || a.user != b.user {
+		t.Fatalf("expected host/port/user to stay identical")
+	}
+}
+
+func TestNewSSHClientCacheKey_DiffKeyPath(t *testing.T) {
+	a := newSSHClientCacheKey(connection.SSHConfig{
+		Host:    "127.0.0.1",
+		Port:    22,
+		User:    "root",
+		KeyPath: "/tmp/a.key",
+	})
+	b := newSSHClientCacheKey(connection.SSHConfig{
+		Host:    "127.0.0.1",
+		Port:    22,
+		User:    "root",
+		KeyPath: "/tmp/b.key",
+	})
+	if a == b {
+		t.Fatalf("expected different cache key when keyPath differs")
+	}
+}