Go: merge duplicate codes (#16783)

### Summary

1. merge heartbeat function.
2. introduce all environments

---------

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

internal/cli/cli.go

@@ -21,6 +21,8 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"ragflow/internal/common"
+
 	//"os/signal"
 	"path/filepath"
 	"strconv"
@@ -482,7 +484,7 @@ Commands:
 
 // HistoryFile returns the path to the history file
 func HistoryFile() string {
-	return os.Getenv("HOME") + "/" + historyFileName
+	return common.GetEnv(common.EnvHome) + "/" + historyFileName
 }
 
 const historyFileName = ".ragflow_cli_history"

internal/cli/filesystem/skill_hub/source/interface.go

@@ -19,8 +19,8 @@ package source
 import (
 	"fmt"
 	"net/url"
-	"os"
 	"path/filepath"
+	"ragflow/internal/common"
 	"strings"
 )
 
@@ -117,9 +117,9 @@ func (r *SourceResolver) Resolve(ref string) (SkillSource, string, error) {
 
 // getHomeDir returns the user's home directory
 func getHomeDir() (string, error) {
-	home := os.Getenv("HOME")
+	home := common.GetEnv(common.EnvHome)
 	if home == "" {
-		home = os.Getenv("USERPROFILE")
+		home = common.GetEnv(common.EnvUserProfile)
 	}
 	if home == "" {
 		return "", fmt.Errorf("cannot determine home directory")

internal/cli/filesystem/skill_install.go

@@ -24,6 +24,7 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
+	"ragflow/internal/common"
 	"strings"
 	"time"
 
@@ -79,10 +80,10 @@ func (a *sourceHTTPClientAdapter) Get(url string) (*http.Response, error) {
 // NewInstallSkillCommand creates a new install-skill command handler
 func NewInstallSkillCommand(client HTTPClientInterface, fileProvider *FileProvider, skillProvider Provider) *SkillInstallCommand {
 	// Log proxy settings
-	if httpProxy := os.Getenv("http_proxy"); httpProxy != "" {
+	if httpProxy := common.GetEnv(common.EnvHttpHTTPProxy); httpProxy != "" {
 		fmt.Printf("Using HTTP proxy: %s\n", httpProxy)
 	}
-	if httpsProxy := os.Getenv("https_proxy"); httpsProxy != "" {
+	if httpsProxy := common.GetEnv(common.EnvHttpHTTPSProxy); httpsProxy != "" {
 		fmt.Printf("Using HTTPS proxy: %s\n", httpsProxy)
 	}