[scripts] Add option to load and compare old regression files

[epernod]

Edit 2026-2-11: To be factorized with the rest of the code when #92 and this one are merged

Add a temporary option: --legacy-regression to read old state.txt.gz file and compare it to current simulation

quickly tested it on the examples/Demo folder:

Compare all scenes from: examples/RegressionStateScenes.regression-tests: 100%|████████████████████████████████████████████████████| 10/10 [00:13<00:00,  1.32s/it]
Compare all scenes from: examples/RegressionTopologyScenes.regression-tests: : 0it [00:00, ?it/s]                                    | 1/2 [00:13<00:13, 13.18s/it]
Compare All sets: 100%|██████████████████████████████████████████████████████████████████████████████████████████████████████████████| 2/2 [00:13<00:00,  6.59s/it]
### Number of sets Done:  2
### Number of scenes Done:  10
### Number of scenes failed:  8
### [Failed] examples\Demos/TriangleSurfaceCutting.scn
    ### Total Error per MechanicalObject: [0.001411652895172418]
    ### Error by Dofs: [3.4497871338524387e-07]
### [Failed] No frames were tested for examples\Demos/chainAll.scn
### [Failed] No frames were tested for examples\Demos/chainHybrid.scn
### [Failed] No frames were tested for examples\Demos/chainHybridNoGroup.scn
### [Failed] examples\Demos/collisionMultiple.scn
    ### Total Error per MechanicalObject: [0.000372312758441868, 0.0015472831183819295, 0.0007623599311863419, 0.0028865856526393606, 0.0007250478446112322, 0.00203
992118274441]
    ### Error by Dofs: [2.068404213565933e-06, 6.447012993258039e-07, 2.8235553006901553e-06, 8.08567409702902e-07, 2.685362387449008e-06, 1.1564179040501191e-06]
### [Success] examples\Demos/liver.scn | Number of key frames compared without error: 2
### [Success] examples\Demos/simpleBoundaryConditions.scn | Number of key frames compared without error: 2
### [Failed] examples\Demos/fallingBeamLagrangianCollision.scn
    ### Total Error per MechanicalObject: [1.2660520042993556e-05, 1.2660520042993556e-05]
    ### Error by Dofs: [6.75227735626323e-09, 6.75227735626323e-09]
### [Failed] examples\Demos/fallingSOFA.scn
    ### Total Error per MechanicalObject: [8.864889117006331e-06, 8.864889117006331e-06]
    ### Error by Dofs: [1.0944307551859667e-08, 1.0944307551859667e-08]
### [Failed] examples\Demos/SofaScene.scn
    ### Total Error per MechanicalObject: [0.0013379029059500456, 9.415874492864297e-05, 3.326468363146977e-06, 7.550511054434961e-06, 5.0259805529949355e-06, 0.000
9196014317737517, 0.0009196014317737517, 3.767619750694152e-06, 0.00032337211637917934, 0.0012090819685236594, 2.403695150876618e-05, 6.397953791482483e-05, 0.00116
85661150702335, 0.0006839340947877948]
    ### Error by Dofs: [5.498984405877704e-07, 6.2772496619095315e-06, 1.108822787715659e-06, 2.1572888726957033e-07, 8.376634254991559e-07, 7.26383437420025e-07, 7
.26383437420025e-07, 1.255873250231384e-06, 3.3684595456164516e-06, 8.292743268337855e-07, 3.4338502155380254e-06, 4.2653025276549886e-06, 9.431526352463548e-07, 1.
6520147217096492e-06]

[epernod]

backup log in verbose for liver and triangleSurfaceCutting, there is something strange in the step/time computation:

compare_legacy_references: ./examples\Demos/TriangleSurfaceCutting.scn:   0%|                                                                            | 0/100.0 [00:00<?, ?it/s]
ref_values[0] len: 2

ref_values[0][0] shape: (1364, 3)

0 | Mo | full_dist: 3.4480638871281006e-13 | error_by_dof: 8.426353585357039e-17 | nbrDofs: 4092
99 | Mo | full_dist: 0.0014116528948276115 | error_by_dof: 3.4497871330098035e-07 | nbrDofs: 4092
compare_legacy_references: ./examples\Demos/TriangleSurfaceCutting.scn:  99%|██████████████████████████████████████████████████████████████████▎| 99/100.0 [00:01<00:00, 95.65it/s]
                                                                                                                                                                                   Test scene: ./examples\Demos/liver.scn vs C:\projects\sofa_plugins\Regression\references\examples\Demos/liver.scn using: 100 0.0001                   | 1/2 [00:01<00:01,  1.16s/it]
legacy_mode=True
                                                                                                                                                                                   ref_times len: 2
compare_legacy_references: ./examples\Demos/liver.scn:   0%|                                                                                             | 0/100.0 [00:00<?, ?it/s]
ref_values[0] len: 2

ref_values[0][0] shape: (181, 3)

0 | dofs | full_dist: 0.0 | error_by_dof: 0.0 | nbrDofs: 543
0 | spheres | full_dist: 1.395528702594252e-15 | error_by_dof: 1.368165394700247e-17 | nbrDofs: 102
99 | dofs | full_dist: 6.657031371972412e-05 | error_by_dof: 1.225972628355877e-07 | nbrDofs: 543
99 | spheres | full_dist: 3.099324840465699e-05 | error_by_dof: 3.03855376516245e-07 | nbrDofs: 102
compare_legacy_references: ./examples\Demos/liver.scn:  99%|██████████████████████████████████████████████████████████████████████████████████▏| 99/100.0 [00:00<00:00, 276.49it/s]
Compare all scenes from: ./examples/RegressionStateScenes.regression-tests: 100%|████████████████████████████████████████████████████████████████████| 2/2 [00:01<00:00,  1.27it/s]
Compare all scenes from: ./examples/RegressionTopologyScenes.regression-tests: : 0it [00:00, ?it/s]                                                  | 1/2 [00:01<00:01,  1.57s/it]
Compare All sets: 100%|██████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 2/2 [00:01<00:00,  1.27it/s]
### Number of sets Done:  2
### Number of scenes Done:  2
### Number of scenes failed:  1
### Failed: ./examples\Demos/TriangleSurfaceCutting.scn
    ### Total Error per MechanicalObject: [0.001411652895172418]
    ### Error by Dofs: [3.4497871338524387e-07]
### Success: ./examples\Demos/liver.scn | Number of key frames compared without error: 2