feat: persist pinned libraries per user with cross-device sync (#20)

Store pinned library IDs on the user record and expose GET/PUT
/me/pinned-libraries endpoints. The web client now loads and saves pins
through the API, migrates legacy localStorage data once, and applies
pinned ordering on both the libraries and home pages.

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: truewhile <truewhile@users.noreply.github.com>

internal/handler/pinned_libraries.go

@@ -0,0 +1,49 @@
+package handler
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/truewhile/MeBox/internal/middleware"
+	"github.com/truewhile/MeBox/internal/service"
+)
+
+type pinnedLibrariesReq struct {
+	LibraryIDs []string `json:"library_ids"`
+}
+
+func getPinnedLibrariesHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		uid, _ := c.Get(middleware.CtxUserID)
+		ids, err := svc.Profile.GetPinnedLibraryIDs(c.Request.Context(), uid.(string))
+		if err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+		if ids == nil {
+			ids = []string{}
+		}
+		c.JSON(http.StatusOK, gin.H{"library_ids": ids})
+	}
+}
+
+func setPinnedLibrariesHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		var req pinnedLibrariesReq
+		if err := c.ShouldBindJSON(&req); err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+		uid, _ := c.Get(middleware.CtxUserID)
+		ids, err := svc.Profile.SetPinnedLibraryIDs(c.Request.Context(), uid.(string), req.LibraryIDs)
+		if err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+		if ids == nil {
+			ids = []string{}
+		}
+		c.JSON(http.StatusOK, gin.H{"library_ids": ids})
+	}
+}

internal/handler/routes_authenticated_core.go

@@ -10,6 +10,8 @@ import (
 func registerAuthedUserAndLicenseRoutes(authed *gin.RouterGroup, svc *service.Container) {
 	authed.GET("/me", meHandler(svc))
 	authed.PATCH("/me", updateProfileHandler(svc))
+	authed.GET("/me/pinned-libraries", getPinnedLibrariesHandler(svc))
+	authed.PUT("/me/pinned-libraries", setPinnedLibrariesHandler(svc))
 	authed.POST("/me/password", changePasswordHandler(svc))
 	authed.POST("/me/logout", logoutHandler(svc))
 

internal/handler/routes_authenticated_test.go

@@ -25,6 +25,8 @@ func TestAuthenticatedRouteSurfacesAreRegistered(t *testing.T) {
 
 	for _, want := range []string{
 		"GET /api/me",
+		"GET /api/me/pinned-libraries",
+		"PUT /api/me/pinned-libraries",
 		"GET /api/auth/permissions",
 		"GET /api/libraries",
 		"GET /api/media",