Version of SWIFT from January 2026.

Major changes since v2025.10:
 - Fixed a bug in the FOF whereby multiple BHs could be seeded in the same halo.
 - Added support for the `Likwid` performance analysis tool.
 - Removed the hard-coded mode for boundary (i.e. stationary) particles. The same feature is now implemented as a forcing scheme.
 - Improved the layout and chunking of fields in hdf5 files to speed up reading.
 - Fixed a bug in the spawning of stars by sink particles making the starts have an invalid position in the tree.
 - Fixed bugs in the check-pointing of arrays in the GEAR module.
 - Reduced the memory usage in FOF by freeing unnecessary foreign arrays prior to the call.
 - Added a mode to run the code without any i/o (useful for performance testing)
 - Fixed a bug preventing the grid from being created in non-periodic very small test cases over MPI.
 - Fixed a series of equation of state edge cases in the planetary model.
 - Added the idealised AGN jet example of Husko+2022 to the public repository.
 - Introduced the multiplexing of critical tasks (cooling, stars-self, hydro & star ghosts) to enhance parallelism (backport from colibre fork).
 - Fixed a bug in the RT loops preventing the code from running following the introduction of the new neighbour finding.
 - Minor formatting, code duplication removals, and documentation improvements.