[PWGHF] taskFlow: Add McGen and efficiencies

[AlexianL]

No description provided.

[github-actions]

O2 linter results: ❌ 0 errors, ⚠️ 0 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/staging for 7ba8cf4 at 2026-06-10 17:10:

## sw/BUILD/O2Physics-latest/log
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGHF/HFC/Tasks/taskFlow.cxx:3833:32: error: invalid initialization of reference of type 'o2::framework::expressions::Node&&' from expression of type 'const float'
ninja: build stopped: subcommand failed.

Full log here.

[alibuild]

Error while checking build/O2Physics/o2 for 1971979 at 2026-06-10 22:36:

## sw/BUILD/O2Physics-latest/log
2026-06-10T22:28:04.466+0200 [780:139706440273536] [buildboxcommon_grpcretrier.cpp:177] [ERROR] Retry limit (0) exceeded for "FindMissingBlobs()", last gRPC error was [14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused]
2026-06-10T22:28:18.446+0200 [28:139666558537344] [buildboxcommon_grpcretrier.cpp:177] [ERROR] Retry limit (0) exceeded for "FindMissingBlobs()", last gRPC error was [14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused]
2026-06-10T22:28:25.016+0200 [1398:139991015509632] [buildboxcommon_grpcretrier.cpp:177] [ERROR] Retry limit (0) exceeded for "FindMissingBlobs()", last gRPC error was [14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused]
2026-06-10T22:28:20.338+0200 [2119:140410781339264] [buildboxcommon_grpcretrier.cpp:177] [ERROR] Retry limit (0) exceeded for "ActionCache.GetActionResult()", last gRPC error was [14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused]
2026-06-10T22:28:20.338+0200 [2119:140410781339264] [executioncontext.cpp:544] [ERROR] Error while querying action cache at "http://localhost:8980": 14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused
2026-06-10T22:28:10.171+0200 [2091:140195654282880] [buildboxcommon_grpcretrier.cpp:177] [ERROR] Retry limit (0) exceeded for "ActionCache.GetActionResult()", last gRPC error was [14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused]
2026-06-10T22:28:10.171+0200 [2091:140195654282880] [executioncontext.cpp:544] [ERROR] Error while querying action cache at "http://localhost:8980": 14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused
c++: fatal error: Killed signal terminated program cc1plus
2026-06-10T22:28:32.229+0200 [2157:140117308558976] [buildboxcommon_grpcretrier.cpp:177] [ERROR] Retry limit (0) exceeded for "ActionCache.GetActionResult()", last gRPC error was [14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused]
2026-06-10T22:28:32.229+0200 [2157:140117308558976] [executioncontext.cpp:544] [ERROR] Error while querying action cache at "http://localhost:8980": 14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused
2026-06-10T22:28:06.403+0200 [2057:139881505713792] [buildboxcommon_grpcretrier.cpp:177] [ERROR] Retry limit (0) exceeded for "ActionCache.GetActionResult()", last gRPC error was [14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused]
2026-06-10T22:28:06.403+0200 [2057:139881505713792] [executioncontext.cpp:544] [ERROR] Error while querying action cache at "http://localhost:8980": 14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused
ninja: build stopped: subcommand failed.

Full log here.