feat: OpsxDB 桌面数据库客户端首版入库

含工作台/连库多引擎字段与 SSH·SSL、结果编辑、Redis 键浏览、
Tauri 桌面与 docs/落地页；排除本地构建产物与 sidecar 二进制。

apps/server/internal/db/redis_ttl_test.go

@@ -0,0 +1,29 @@
+package db
+
+import (
+	"testing"
+	"time"
+)
+
+func TestTTLSecondsSentinels(t *testing.T) {
+	cases := []struct {
+		in   time.Duration
+		want int64
+	}{
+		{time.Duration(-1), -1},
+		{-1 * time.Nanosecond, -1},
+		{-1 * time.Second, -1},
+		{time.Duration(-2), -2},
+		{-2 * time.Nanosecond, -2},
+		{-2 * time.Second, -2},
+		{0, 0},
+		{5 * time.Second, 5},
+		{1500 * time.Millisecond, 1},
+	}
+	for _, c := range cases {
+		got := ttlSeconds(c.in)
+		if got != c.want {
+			t.Fatalf("ttlSeconds(%v)=%d want %d", c.in, got, c.want)
+		}
+	}
+}