Add SimPulse data type for storing simulated pulses pre-digitization (#106)

### Briefly, what does this PR introduce?

This PR adds a new data type, `edm4eic::SimPulse`, to represent
simulated pulses before digitization.

The new structure is modeled consistently with the edmhep simulated hit
types and aligns with existing waveform structures such as
`edm4hep::RawTimeSeries` (generic digitization output) and
`edm4hep::TimeSeries` (generic measured time series).

`SimPulse` defines four one-to-many relations relations:
- **`SimCalorimeterHit`**: Pulses can be constructed from contributions
of one or more simulated calorimeter hits.
- **`SimTrackerHit`**: Pulses can be constructed from one or more
simulated tracker hits.
- **`SimPulse`**: Pulses can be constructed out of other pulses.
- **`MCParticle`**: Each pulse can be attributed to a single MCParticle
(primary pulse), multiple MCParticles (overlayed pulses), or zero
MCParticles (noise pulse).

Storing pulses at the simulation level ensures conceptual clarity and
consistency within our data model. The simulated pulse data to be stored
in this structure have no equivalent in real detector output, and are
therefore not digitization output.

By using a Simulation structure, we gain direct `Relation` support with
other simulation entities, enabling efficient backward navigation
through the simulation chain. While Associations are used to link
digitization and reconstruction structures to simulation, Relations are
preferred for internal connections within the same domain (e.g. within
Simulation or within Reconstruction). This design avoids introducing
redundant Association types and keeps the data model consistent, clean
and efficient.

### What kind of change does this PR introduce?
- [ ] Bug fix (issue #__)
- [X] New feature (issue #__)
- [ ] Documentation update
- [ ] Other: __

### Please check if this PR fulfills the following:
- [ ] Tests for the changes have been added
- [X] Documentation has been added / updated
- [X] Changes have been communicated to collaborators

### Does this PR introduce breaking changes? What changes might users
need to make to their code?
No

### Does this PR change default behavior?
No

---------

Co-authored-by: Dmitry Kalinkin <dmitry.kalinkin@gmail.com>
Co-authored-by: Derek M Anderson <derek.murphy.anderson@protonmail.com>
Co-authored-by: Simon Gardner <simon.gardner@glasgow.ac.uk>

Author: 4 people

CMakeLists.txt

@@ -7,7 +7,7 @@ project(EDM4EIC
   LANGUAGES CXX)
 
 SET( ${PROJECT_NAME}_VERSION_MAJOR 8 )
-SET( ${PROJECT_NAME}_VERSION_MINOR 0 )
+SET( ${PROJECT_NAME}_VERSION_MINOR 1 )
 SET( ${PROJECT_NAME}_VERSION_PATCH 0 )
 SET( ${PROJECT_NAME}_VERSION  "${${PROJECT_NAME}_VERSION_MAJOR}.${${PROJECT_NAME}_VERSION_MINOR}.${${PROJECT_NAME}_VERSION_PATCH}" )
 

edm4eic.yaml

@@ -7,9 +7,9 @@
 ## Patch level changes are required to be schema invariant.
 ##
 ## If there are schema version changes that can be evolved, see the podio documentation
-## for an example: https://github.com/hegner/podio/blob/master/tests/schema_evolution.yaml
+## for an example: https://github.com/AIDASoft/podio/tree/master/tests/schema_evolution
 ##
-schema_version: 800
+schema_version: 801
 
 options :
   # should getters / setters be prefixed with get / set?
@@ -203,6 +203,27 @@ datatypes:
       - float             floatData       // Iff elementType==1, values are stored here
       - int64_t           int64Data       // Iff elementType==7, values are stored here
 
+  ## ==========================================================================
+  ## Simulation info
+  ## ==========================================================================
+
+  edm4eic::SimPulse:
+    Description: "Simulated pulse prior to digitization."
+    Author: "D. Anderson, S. Gardner, S. Joosten., D. Kalinkin"
+    Members:
+      - uint64_t            cellID          // ID of the readout cell for this pulse.
+      - float               integral        // Total pulse integral in relevant units.
+      - edm4hep::Vector3f   position        // Position the pulse is evaluated in world coordinates [mm].
+      - float               time            // Start time for the pulse in [ns].
+      - float               interval        // Time interval between amplitude values [ns].
+    VectorMembers:
+      - float               amplitude       // Pulse amplitude in relevant units, sum of amplitude values equals integral
+    OneToManyRelations:
+      - edm4hep::SimCalorimeterHit calorimeterHits // SimCalorimeterHits used to create this pulse
+      - edm4hep::SimTrackerHit     trackerHits     // SimTrackerHits used to create this pulse
+      - edm4eic::SimPulse          pulses          // SimPulses used to create this pulse
+      - edm4hep::MCParticle        particles       // MCParticle that caused the pulse
+
   ## ==========================================================================
   ## Particle info
   ## ==========================================================================