chore: remove usage tracking and logging functionality

- Deleted the `LoggerPlugin` along with associated usage tracking and in-memory statistics logic.
- Removed all related tests (`logger_plugin_test.go`, `usage_tab_test.go`) and external-facing handler (`usage.go`) for usage statistics export/import.
- Cleaned up TUI integration by deleting `usage_tab.go`.

internal/api/handlers/management/handler.go

@@ -15,7 +15,6 @@ import (
 	"github.com/gin-gonic/gin"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/buildinfo"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
-	"github.com/router-for-me/CLIProxyAPI/v6/internal/usage"
 	sdkAuth "github.com/router-for-me/CLIProxyAPI/v6/sdk/auth"
 	coreauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
 	"golang.org/x/crypto/bcrypt"
@@ -41,7 +40,6 @@ type Handler struct {
 	attemptsMu          sync.Mutex
 	failedAttempts      map[string]*attemptInfo // keyed by client IP
 	authManager         *coreauth.Manager
-	usageStats          *usage.RequestStatistics
 	tokenStore          coreauth.Store
 	localPassword       string
 	allowRemoteOverride bool
@@ -60,7 +58,6 @@ func NewHandler(cfg *config.Config, configFilePath string, manager *coreauth.Man
 		configFilePath:      configFilePath,
 		failedAttempts:      make(map[string]*attemptInfo),
 		authManager:         manager,
-		usageStats:          usage.GetRequestStatistics(),
 		tokenStore:          sdkAuth.GetTokenStore(),
 		allowRemoteOverride: envSecret != "",
 		envSecret:           envSecret,
@@ -124,9 +121,6 @@ func (h *Handler) SetAuthManager(manager *coreauth.Manager) {
 	h.mu.Unlock()
 }
 
-// SetUsageStatistics allows replacing the usage statistics reference.
-func (h *Handler) SetUsageStatistics(stats *usage.RequestStatistics) { h.usageStats = stats }
-
 // SetLocalPassword configures the runtime-local password accepted for localhost requests.
 func (h *Handler) SetLocalPassword(password string) { h.localPassword = password }
 

internal/api/handlers/management/usage.go

@@ -1,79 +0,0 @@
-package management
-
-import (
-	"encoding/json"
-	"net/http"
-	"time"
-
-	"github.com/gin-gonic/gin"
-	"github.com/router-for-me/CLIProxyAPI/v6/internal/usage"
-)
-
-type usageExportPayload struct {
-	Version    int                      `json:"version"`
-	ExportedAt time.Time                `json:"exported_at"`
-	Usage      usage.StatisticsSnapshot `json:"usage"`
-}
-
-type usageImportPayload struct {
-	Version int                      `json:"version"`
-	Usage   usage.StatisticsSnapshot `json:"usage"`
-}
-
-// GetUsageStatistics returns the in-memory request statistics snapshot.
-func (h *Handler) GetUsageStatistics(c *gin.Context) {
-	var snapshot usage.StatisticsSnapshot
-	if h != nil && h.usageStats != nil {
-		snapshot = h.usageStats.Snapshot()
-	}
-	c.JSON(http.StatusOK, gin.H{
-		"usage":           snapshot,
-		"failed_requests": snapshot.FailureCount,
-	})
-}
-
-// ExportUsageStatistics returns a complete usage snapshot for backup/migration.
-func (h *Handler) ExportUsageStatistics(c *gin.Context) {
-	var snapshot usage.StatisticsSnapshot
-	if h != nil && h.usageStats != nil {
-		snapshot = h.usageStats.Snapshot()
-	}
-	c.JSON(http.StatusOK, usageExportPayload{
-		Version:    1,
-		ExportedAt: time.Now().UTC(),
-		Usage:      snapshot,
-	})
-}
-
-// ImportUsageStatistics merges a previously exported usage snapshot into memory.
-func (h *Handler) ImportUsageStatistics(c *gin.Context) {
-	if h == nil || h.usageStats == nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "usage statistics unavailable"})
-		return
-	}
-
-	data, err := c.GetRawData()
-	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "failed to read request body"})
-		return
-	}
-
-	var payload usageImportPayload
-	if err := json.Unmarshal(data, &payload); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid json"})
-		return
-	}
-	if payload.Version != 0 && payload.Version != 1 {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "unsupported version"})
-		return
-	}
-
-	result := h.usageStats.MergeSnapshot(payload.Usage)
-	snapshot := h.usageStats.Snapshot()
-	c.JSON(http.StatusOK, gin.H{
-		"added":           result.Added,
-		"skipped":         result.Skipped,
-		"total_requests":  snapshot.TotalRequests,
-		"failed_requests": snapshot.FailureCount,
-	})
-}