DOC: give this branch its changelog line

Under Changed rather than Fixed: nothing about the API moves, but every
number out of the generalized equations of motion does, so a study built on
the old ones will not reproduce. The entry says that first and carries the
one measured comparison the suite has.

Signed-off-by: thc1006 <84045975+thc1006@users.noreply.github.com>

Author: thc1006

CHANGELOG.md

@@ -52,6 +52,7 @@ Attention: The newest changes should be on top -->
 
 ### Changed
 
+- BUG: Negate `com_to_cdm_function` and `nozzle_to_cdm` where `u_dot_generalized` reads them. Both are defined pointing at the center of dry mass and the derivation measures from it, so the moment arm they formed had the wrong sign. Every result out of the generalized equations of motion changes, so a study built on the old numbers will not reproduce. On the measured 2024 Defiance flight the apogee error against 9308.32 m AGL goes from 0.6928 % to 0.6483 %. [#1186](https://github.com/RocketPy-Team/RocketPy/issues/1186)
 - ENH: Number the simulations of a serial Monte Carlo run from zero, as the parallel path already did — the two used to name the same simulation `1, 2, 3` and `0, 1, 2`. The `index` field written into the inputs and outputs rows shifts by one for serial runs, so code reading indices off those files has to expect a run of `n` simulations to be numbered `0` to `n - 1`. An append onto a study written before this release is refused rather than continued, since its rows do not record which root drew them. [#1187](https://github.com/RocketPy-Team/RocketPy/pull/1187)
 - MNT: Store the reference-area correction factor on each rocket aero surface component, so it is carried with the surface instead of being recomputed at every lift evaluation. `Rocket.aerodynamic_surfaces`, `rail_buttons` and `sensors` now yield `(component, position, ref_factor)`, so code that unpacks a pair from them (`for surface, position in rocket.aerodynamic_surfaces`) has to take the third field or absorb it. Simulation results are unchanged, and `.rpy` files written before this still load. [#1129](https://github.com/RocketPy-Team/RocketPy/pull/1129) [#561](https://github.com/RocketPy-Team/RocketPy/issues/561)
 - ENH: Compute the rocket static margin lazily [#1135](https://github.com/RocketPy-Team/RocketPy/pull/1135) [#780](https://github.com/RocketPy-Team/RocketPy/issues/780)