Add citation page to the docs site

Adds a Citing page with the Zenodo DOI badge, guidance on concept versus version DOIs, and APA and BibTeX entries taken from the DataCite record. The docs home page gets the DOI badge and a short citation section.

Author: AdrianCurtin

docs/CITING.md

@@ -0,0 +1,50 @@
+# Citing processFNIRS2
+
+[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.23348858.svg)](https://doi.org/10.5281/zenodo.23348858)
+
+If you use processFNIRS2 in your research, please cite the software. Each
+release is archived on [Zenodo](https://doi.org/10.5281/zenodo.23348858).
+
+## Which DOI to use
+
+| DOI | Points to | Use it for |
+|-----|-----------|------------|
+| [10.5281/zenodo.23348858](https://doi.org/10.5281/zenodo.23348858) | processFNIRS2 as a whole; always resolves to the latest release | Citing the toolbox in general |
+| Version DOI, listed on the [Zenodo record](https://doi.org/10.5281/zenodo.23348858) under "Versions" | One specific release | Methods sections and code-availability statements, so readers can reproduce your analysis |
+
+Check the version you ran with `pf2_base.pf2version()`. For v1.2.0 the version
+DOI is [10.5281/zenodo.23348859](https://doi.org/10.5281/zenodo.23348859).
+
+## APA
+
+> Curtin, A., & Ayaz, H. (2026). *processFNIRS2* (Version v1.2.0) [Computer
+> software]. Zenodo. https://doi.org/10.5281/zenodo.23348858
+
+## BibTeX
+
+```bibtex
+@software{curtin2026processfnirs2,
+  author    = {Curtin, Adrian and Ayaz, Hasan},
+  title     = {processFNIRS2},
+  version   = {v1.2.0},
+  publisher = {Zenodo},
+  year      = {2026},
+  doi       = {10.5281/zenodo.23348858},
+  url       = {https://doi.org/10.5281/zenodo.23348858},
+  license   = {GPL-3.0-or-later}
+}
+```
+
+For a specific release, replace the `doi`, `url` and `version` with that
+release's values from Zenodo.
+
+## Other formats
+
+- **GitHub:** the "Cite this repository" button on the
+  [repository page](https://github.com/AyazLab/processFNIRS2) exports APA and
+  BibTeX from
+  [`CITATION.cff`](https://github.com/AyazLab/processFNIRS2/blob/master/CITATION.cff).
+- **Zenodo:** the record's "Citation" box offers further styles and export
+  formats (RIS, CSL JSON, DataCite XML).
+
+A companion publication will be listed here when available.

docs/README.md

@@ -1,5 +1,7 @@
 # processFNIRS2 Documentation
 
+[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.23348858.svg)](https://doi.org/10.5281/zenodo.23348858)
+
 Reference documentation for the processFNIRS2 MATLAB fNIRS analysis toolbox.
 New here? Start with the [project README](https://github.com/AyazLab/processFNIRS2/blob/master/README.md)
 for installation and a quick start, then come back for the deeper references
@@ -18,6 +20,16 @@ below. Runnable tutorials live in
 | [EXPLORERNIRS_PIPELINE.md](EXPLORERNIRS_PIPELINE.md) | The group-analysis layer (exploreFNIRS): Experiment class, grouping, statistics. |
 | [ARCHITECTURE.md](ARCHITECTURE.md) | How the toolbox fits together: data flow, package map, and where new code belongs. |
 
+## Citing
+
+If you use processFNIRS2 in your research, please cite it:
+
+> Curtin, A., & Ayaz, H. (2026). *processFNIRS2* (Version v1.2.0) [Computer
+> software]. Zenodo. https://doi.org/10.5281/zenodo.23348858
+
+See [Citing processFNIRS2](CITING.md) for BibTeX and for choosing between the
+project DOI and a per-version DOI.
+
 ## Also useful
 
 - [Project README](https://github.com/AyazLab/processFNIRS2/blob/master/README.md) — overview, install, quick start.

mkdocs.yml

@@ -57,3 +57,4 @@ nav:
       - CLI/UX Guide: CLI_UX_GUIDE.md
       - exploreFNIRS Pipeline: EXPLORERNIRS_PIPELINE.md
   - Architecture: ARCHITECTURE.md
+  - Citing: CITING.md