feat(api): add admin endpoints for binding management

Implement handlers for creating, listing, and updating model bindings.
Register new routes in the admin server group and add DTO definitions.
Update provider handlers to trigger binding synchronization on changes
to ensure upstream mappings remain current.

internal/api/binding_handler.go

@@ -0,0 +1,160 @@
+package api
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/ez-api/ez-api/internal/dto"
+	"github.com/ez-api/ez-api/internal/model"
+	groupx "github.com/ez-api/foundation/group"
+	"github.com/gin-gonic/gin"
+)
+
+// CreateBinding godoc
+// @Summary      Create a new binding
+// @Description  Create a new (namespace, public_model) binding to a route group and selector
+// @Tags         admin
+// @Accept       json
+// @Produce      json
+// @Security     AdminAuth
+// @Param        binding  body      dto.BindingDTO  true  "Binding Info"
+// @Success      201      {object}  model.Binding
+// @Failure      400      {object}  gin.H
+// @Failure      500      {object}  gin.H
+// @Router       /admin/bindings [post]
+func (h *Handler) CreateBinding(c *gin.Context) {
+	var req dto.BindingDTO
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	ns := strings.TrimSpace(req.Namespace)
+	pm := strings.TrimSpace(req.PublicModel)
+	if ns == "" || pm == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "namespace and public_model required"})
+		return
+	}
+
+	rg := groupx.Normalize(req.RouteGroup)
+	if strings.TrimSpace(rg) == "" {
+		rg = "default"
+	}
+
+	st := strings.TrimSpace(req.Status)
+	if st == "" {
+		st = "active"
+	}
+
+	selectorType := strings.TrimSpace(req.SelectorType)
+	if selectorType == "" {
+		selectorType = "exact"
+	}
+
+	b := model.Binding{
+		Namespace:     ns,
+		PublicModel:   pm,
+		RouteGroup:    rg,
+		SelectorType:  selectorType,
+		SelectorValue: strings.TrimSpace(req.SelectorValue),
+		Status:        st,
+	}
+
+	if err := h.db.Create(&b).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to create binding", "details": err.Error()})
+		return
+	}
+
+	if err := h.sync.SyncBindings(h.db); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to sync bindings", "details": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusCreated, b)
+}
+
+// ListBindings godoc
+// @Summary      List bindings
+// @Description  List all configured bindings
+// @Tags         admin
+// @Produce      json
+// @Security     AdminAuth
+// @Success      200  {array}   model.Binding
+// @Failure      500  {object}  gin.H
+// @Router       /admin/bindings [get]
+func (h *Handler) ListBindings(c *gin.Context) {
+	var out []model.Binding
+	if err := h.db.Find(&out).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to list bindings", "details": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, out)
+}
+
+// UpdateBinding godoc
+// @Summary      Update a binding
+// @Description  Update an existing binding
+// @Tags         admin
+// @Accept       json
+// @Produce      json
+// @Security     AdminAuth
+// @Param        id       path      int            true  "Binding ID"
+// @Param        binding  body      dto.BindingDTO true  "Binding Info"
+// @Success      200      {object}  model.Binding
+// @Failure      400      {object}  gin.H
+// @Failure      404      {object}  gin.H
+// @Failure      500      {object}  gin.H
+// @Router       /admin/bindings/{id} [put]
+func (h *Handler) UpdateBinding(c *gin.Context) {
+	idParam := c.Param("id")
+	id, err := strconv.Atoi(idParam)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid id"})
+		return
+	}
+
+	var existing model.Binding
+	if err := h.db.First(&existing, id).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "binding not found"})
+		return
+	}
+
+	var req dto.BindingDTO
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	if ns := strings.TrimSpace(req.Namespace); ns != "" {
+		existing.Namespace = ns
+	}
+	if pm := strings.TrimSpace(req.PublicModel); pm != "" {
+		existing.PublicModel = pm
+	}
+	if rg := strings.TrimSpace(req.RouteGroup); rg != "" {
+		existing.RouteGroup = groupx.Normalize(rg)
+	}
+	if st := strings.TrimSpace(req.Status); st != "" {
+		existing.Status = st
+	}
+	if t := strings.TrimSpace(req.SelectorType); t != "" {
+		existing.SelectorType = t
+	}
+	if req.SelectorValue != "" {
+		existing.SelectorValue = strings.TrimSpace(req.SelectorValue)
+	}
+
+	if err := h.db.Save(&existing).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to update binding", "details": err.Error()})
+		return
+	}
+
+	if err := h.sync.SyncBindings(h.db); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to sync bindings", "details": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, existing)
+}
+