feat: bootstrap MediaStationGo (Go + React rewrite of MediaStation)

Adopt the cropflre/nowen-video tech stack and rebuild the project from
scratch:

  - Backend: Go 1.25 + Gin + GORM + SQLite (WAL) + JWT + WebSocket hub.
    Layered packages config / database / model / repository / service /
    middleware / handler. Default admin (admin/admin123) seeded on first
    run; /api routes for auth, libraries, media, stream and admin
    panels. WebSocket scan-progress events at /api/ws.
  - Frontend: React 18 + Vite 5 + Tailwind 3.4 + Zustand + axios +
    react-router 6 + lucide-react + framer-motion + hls.js. Pages for
    Login / Home / Library / Search / MediaDetail / Player / Admin
    (Library, Users, Settings tabs).
  - Distribution: multi-arch Dockerfile (frontend -> backend -> Alpine
    runtime), docker-compose.yml, GitHub Actions for CI and GHCR
    publish, Makefile, env-prefixed config (MEDIASTATION_*).
  - Docs: README, CONTRIBUTING, .env.example, config.example.yaml.

Backend builds, vets and tests pass. Frontend builds via tsc -b && vite
build (250 kB JS / 16 kB CSS, gzipped 84 / 4 kB).

internal/handler/admin.go

@@ -0,0 +1,73 @@
+// Package handler — admin endpoints (users / settings / logs).
+package handler
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/ShukeBta/MediaStationGo/internal/service"
+)
+
+func listUsersHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		users, err := svc.Repo.User.List(c.Request.Context())
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+		c.JSON(http.StatusOK, users)
+	}
+}
+
+func deleteUserHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		if err := svc.Repo.User.Delete(c.Request.Context(), c.Param("id")); err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+		c.Status(http.StatusNoContent)
+	}
+}
+
+type settingReq struct {
+	Key   string `json:"key" binding:"required"`
+	Value string `json:"value"`
+}
+
+func listSettingsHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		settings, err := svc.Repo.Setting.All(c.Request.Context())
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+		c.JSON(http.StatusOK, settings)
+	}
+}
+
+func updateSettingHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		var req settingReq
+		if err := c.ShouldBindJSON(&req); err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+		if err := svc.Repo.Setting.Set(c.Request.Context(), req.Key, req.Value); err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+		c.Status(http.StatusNoContent)
+	}
+}
+
+func recentLogsHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		rows, err := svc.Repo.Log.Recent(c.Request.Context(), 200)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+		c.JSON(http.StatusOK, rows)
+	}
+}