docs: add contribution guidelines

[gomezzz]

Summary

• Add CONTRIBUTING.md for AnomalyMatch covering only project-specific technical detail: conda environment setup, the develop/main branching model, Ruff, license headers, test commands, and CI gates.

• Link the guidelines from a callout near the top of the README.

• Everything that is not AnomalyMatch-specific (code of conduct, CLA, licensing, general PR workflow) lives in one central document, now published:

  https://www.cosmos.esa.int/web/data-science/contributing-to-our-software

  CONTRIBUTING.md points at it in a prominent block right under the title.

This split means the CLA and conduct text is written and maintained once, and stays consistent across AnomalyMatch, Cutana, and any future project. All previously open placeholders are resolved: the governance page is live, and the CLA download link and submission address now live there rather than being duplicated per repository.

Branching model corrected

The earlier draft told contributors to target main. A develop branch has now been created on this repository and the guidelines describe the two-branch model used across our projects: develop for features, fixes, and refactors; main for releases and hotfixes.

Note this PR still targets main. Since develop was branched from main and the two are currently identical, develop can be fast-forwarded after merge, or this PR retargeted to develop if you would rather it went that way first.

Test plan

• License-header CI check passes on CONTRIBUTING.md
• README link resolves
• Governance link resolves (verified: HTTP 200)

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
__init__.py	8	0	100%
data_io
SessionIOHandler.py	326	41	87%	111, 128–129, 173–174, 184–185, 215–216, 282–283, 286, 326–328, 370, 388–390, 455, 530, 553, 567–568, 570–571, 573–575, 719–724, 738, 742–743, 747–749
checkpoint_io.py	148	25	83%	68, 74, 76, 78, 95–109, 120, 122, 161, 182, 228, 281
find_images_in_folder.py	21	0	100%
load_images.py	91	28	69%	51–53, 58–60, 81, 93, 110, 140–147, 150, 156–157, 189, 248, 256, 277, 285, 292–294
metadata_handler.py	80	8	90%	70–71, 117, 122–123, 170–172
save_config.py	33	3	91%	92–94
datasets
AnomalyDetectionDataset.py	248	39	84%	126–127, 356, 362–363, 365, 369, 371–372, 374, 395–396, 398, 404–405, 409, 422–423, 484–485, 491–496, 498–499, 503–506, 508–510, 512–514, 525
BasicDataset.py	52	4	92%	59, 61, 97, 103
Label.py	5	0	100%
SSL_Dataset.py	68	3	96%	136, 139, 209
__init__.py	0	0	100%
data_utils.py	56	2	96%	80, 199
datasets/augmentation
randaugment.py	92	11	88%	222, 225–226, 245, 328–330, 332–335
randaugment_multispectral.py	77	23	70%	77–79, 120–121, 134–135, 148–149, 166, 170, 174, 248, 253, 270–272, 274–277, 280–281
image_processing
transforms.py	57	3	95%	46–47, 76
models
FixMatch.py	214	29	86%	108, 201–202, 217, 222, 254, 281–282, 285, 288–290, 293, 301, 306–307, 366, 404, 430–434, 495, 497–498, 502, 519–520
pipeline
SessionTracker.py	122	3	98%	127, 219–220
session.py	541	85	84%	146–149, 399–402, 447, 460, 612, 669, 671–672, 680, 683, 694, 702, 732, 736, 740–741, 745, 750–751, 758, 762–763, 775, 785–786, 788, 792, 806–807, 809–811, 813, 816–817, 875–876, 878–881, 883–887, 893, 899, 904–908, 910, 918, 921–922, 938, 979–980, 986–987, 991–993, 995, 1020, 1046, 1080–1081, 1089, 1100, 1108, 1112, 1116, 1121, 1124, 1168, 1171
utils
accuracy.py	13	0	100%
consistency_loss.py	18	0	100%
create_model_string.py	4	0	100%
cross_entropy_loss.py	9	0	100%
cutana_stream_utils.py	70	9	87%	64–65, 88, 108, 118–122
get_cosine_schedule_with_warmup.py	11	1	91%	39
get_default_cfg.py	61	0	100%
get_net_builder.py	55	7	87%	81–82, 89, 92, 170–171, 175
get_optimizer.py	21	2	90%	54, 58
print_cfg.py	45	4	91%	89, 95, 117, 119
set_log_level.py	15	0	100%
set_seeds.py	13	2	85%	25–26
validate_config.py	131	11	92%	180, 199, 214, 228, 244, 248, 264, 290, 379–381
TOTAL	2705	343	87%

Tests	Skipped	Failures	Errors	Time
376	0 💤	0 ❌	0 🔥	47.539s ⏱️