Replace getStorageForRequest with s.storage (bd-32)

- Replaced all getStorageForRequest(req) calls with direct s.storage access
- Updated 5 handler files: server_issues_epics.go (~8 calls), server_labels_deps_comments.go (~4 calls), server_compact.go (~2 calls), server_export_import_auto.go (~2 calls), server_routing_validation_diagnostics.go (~1 call)
- Only remaining references are in server_cache_storage.go (to be deleted in bd-33) and server_eviction_test.go (to be deleted in bd-34)
- Part of bd-29 epic to remove daemon storage cache

Amp-Thread-ID: https://ampcode.com/threads/T-239a5531-68a5-4c98-b85d-0e3512b2553c
Co-authored-by: Amp <amp@ampcode.com>

internal/rpc/server_routing_validation_diagnostics.go

@@ -294,20 +294,7 @@ func (s *Server) handleHealth(req *Request) Response {
 	var m runtime.MemStats
 	runtime.ReadMemStats(&m)
 
-	store, err := s.getStorageForRequest(req)
-	if err != nil {
-		data, _ := json.Marshal(HealthResponse{
-			Status:  "unhealthy",
-			Version: ServerVersion,
-			Uptime:  time.Since(s.startTime).Seconds(),
-			Error:   fmt.Sprintf("storage error: %v", err),
-		})
-		return Response{
-			Success: false,
-			Data:    data,
-			Error:   fmt.Sprintf("storage error: %v", err),
-		}
-	}
+	store := s.storage
 
 	healthCtx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()