docs: regenerate swagger docs with new API endpoints

Add comprehensive API documentation for new endpoints including:
- Bindings CRUD and batch operations
- Namespaces management
- Master tenant CRUD, access settings, and realtime stats
- Provider CRUD with preset/custom/google variants
- Model registry status, refresh, check, and rollback
- Log management with stats and webhook config
- Key access settings endpoints
- Internal stats flush endpoint
- Health check endpoint

Also adds swagger annotations for FlushStats internal handler.

internal/api/internal_handler.go

@@ -29,6 +29,17 @@ type statsFlushEntry struct {
 	LastAccessedAt int64  `json:"last_accessed_at"`
 }
 
+// FlushStats godoc
+// @Summary      Flush key stats
+// @Description  Internal endpoint for flushing accumulated key usage stats from DP to CP database
+// @Tags         internal
+// @Accept       json
+// @Produce      json
+// @Param        request  body      statsFlushRequest  true  "Stats to flush"
+// @Success      200      {object}  gin.H
+// @Failure      400      {object}  gin.H
+// @Failure      500      {object}  gin.H
+// @Router       /internal/stats/flush [post]
 func (h *InternalHandler) FlushStats(c *gin.Context) {
 	if h == nil || h.db == nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "database not configured"})