GPU/TPC: Simplify pad indexing in noisy-pad filter

[fweig]

This PR fixes an issue, where pad indexing in the pad filter diverged between GPU and CPU version.

As a side effect it also simplifies the indexing scheme used in the pad filter.

Additionally, renamed several related constants with confusing / ambiguous names.

[alibuild]

Error while checking build/O2/fullCI_slc9 for f4c88b9 at 2026-04-14 20:37:

## sw/BUILD/O2-latest/log
/sw/SOURCES/O2/slc9_x86-64-slc9_x86-64/0/GPU/GPUTracking/DataTypes/TPCPadGainCalib.cxx:50:29: error: 'TPC_PADS_IN_SECTOR' was not declared in this scope; did you mean 'TPC_REAL_PADS_IN_SECTOR'?
/sw/SOURCES/O2/slc9_x86-64-slc9_x86-64/0/GPU/GPUTracking/DataTypes/TPCPadBitMap.cxx:43:29: error: 'TPC_PADS_IN_SECTOR' was not declared in this scope; did you mean 'TPC_REAL_PADS_IN_SECTOR'?
/sw/SOURCES/O2/slc9_x86-64-slc9_x86-64/0/GPU/GPUTracking/DataTypes/CalibdEdxContainer.cxx:268:42: error: 'TPC_PADS_IN_SECTOR' was not declared in this scope; did you mean 'TPC_FEC_IDS_IN_SECTOR'?
ninja: build stopped: subcommand failed.

Full log here.

[alibuild]

Error while checking build/O2/fullCI_slc9 for 92a15de at 2026-04-15 00:10:

## sw/BUILD/O2-full-system-test-latest/log
command /sw/slc9_x86-64/O2/slc9_x86-64-slc9_x86-64-local11/prodtests/full-system-test/dpl-workflow.sh had nonzero exit code 1
[9133:BadMapCalibSpec]: [00:10:33][ERROR] Insufficient statistics: 0 entries in lowE histo, do nothing
[9716:qc-task-ITS-ITSTrackTask]: [00:10:49][ERROR] Exception while running: Inconsistent type and payload size at Vertices(DS/tracks1/0): type size 48  payload size 260. Rethrowing.
[9716:qc-task-ITS-ITSTrackTask]: [00:10:49][FATAL] Unhandled o2::framework::runtime_error reached the top of main of o2-qc, device shutting down. Reason: Inconsistent type and payload size at Vertices(DS/tracks1/0): type size 48  payload size 260
[ERROR] Workflow crashed - PID 9716 (qc-task-ITS-ITSTrackTask) did not exit correctly however it's not clear why. Exit code forced to 128.
[9497:o2-eve-export]: [00:10:52][ERROR] filesystem problem during DirectoryLoader::canCreateNextFile: filesystem error: directory iterator cannot open directory: No such file or directory [jsons]
[ERROR]  - Device qc-task-ITS-ITSTrackTask: pid 9716 (exit 128)
[INFO]    - First error: [00:10:49][FATAL] Unhandled o2::framework::runtime_error reached the top of main of o2-qc, device shutting down. Reason: Inconsistent type and payload size at Vertices(DS/tracks1/0): type size 48  payload size 260
[ERROR] SEVERE: Device qc-task-ITS-ITSTrackTask (9716) had at least one message above severity 7: Unhandled o2::framework::runtime_error reached the top of main of o2-qc, device shutting down. Reason: Inconsistent type and payload size at Vertices(DS/tracks1/0): type size 48  payload size 260


## sw/BUILD/o2checkcode-latest/log
--
========== List of errors found ==========
++ GRERR=0
++ grep -v clang-diagnostic-error error-log.txt
++ grep ' error:'
grep: error-log.txt: binary file matches
++ GRERR=1
++ [[ 1 == 0 ]]
++ mkdir -p /sw/INSTALLROOT/5b12ad82680838c956b58db4e785f8e314ebd387/slc9_x86-64/o2checkcode/1.0-local116/etc/modulefiles
++ cat
--

Full log here.

[davidrohr]

Errors unrelated, merging