feat(auth): track unique tools in access metrics

* Add tool tracking to AccessTracker and metrics
* Update tests to validate tool tracking functionality
* Modify middleware to record tool usage
* Enhance observability with tool context
* Update UI to display unique tools in metrics

internal/auth/middleware.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"git.warky.dev/wdevs/amcs/internal/config"
+	"git.warky.dev/wdevs/amcs/internal/observability"
 	"git.warky.dev/wdevs/amcs/internal/requestip"
 )
 
@@ -23,7 +24,14 @@ func Middleware(cfg config.AuthConfig, keyring *Keyring, oauthRegistry *OAuthReg
 	}
 	recordAccess := func(r *http.Request, keyID string) {
 		if tracker != nil {
-			tracker.Record(keyID, r.URL.Path, requestip.FromRequest(r), r.UserAgent(), time.Now())
+			tracker.Record(
+				keyID,
+				r.URL.Path,
+				requestip.FromRequest(r),
+				r.UserAgent(),
+				observability.MCPToolFromContext(r.Context()),
+				time.Now(),
+			)
 		}
 	}
 	return func(next http.Handler) http.Handler {