ENH: deprecate solution_array, get_solution_at_time and the raw export

Flight.solution_array and Flight.get_solution_at_time now warn and point to the
named queries on flight.solution (removal targeted v1.14); they still return the
canonical projection. The no-arguments FlightDataExporter fast path now writes
flight.solution.canonical_array (so it works for reduced-state flights too),
corrects its header to include the missing Vx/Vy/Vz columns, and warns that
explicit variable names will be required.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: MateusStano

rocketpy/simulation/flight.py

@@ -1305,6 +1305,11 @@ def __cache_sensor_data(self):
                 sensor_data[sensor] = sensor.measured_data[:]
         self.sensor_data = sensor_data
 
+    @deprecated(
+        reason="Flight.get_solution_at_time is deprecated",
+        version="v1.14",
+        alternative="flight.solution.at(t)",
+    )
     def get_solution_at_time(self, t, atol=1e-3):
         """Returns the solution state vector at a given time. If the time is
         not found in the solution, the closest time is used and a warning is
@@ -1399,6 +1404,12 @@ def lateral_surface_wind(self):
         return -wind_u * np.cos(heading_rad) + wind_v * np.sin(heading_rad)
 
     @cached_property
+    @deprecated(
+        reason="Flight.solution_array is deprecated",
+        version="v1.14",
+        alternative="flight.solution['name'] for a single variable, or "
+        "flight.solution.canonical_array for the full 14-column table",
+    )
     def solution_array(self):
         """Returns solution array of the rocket flight."""
         return self.solution.canonical_array

rocketpy/simulation/flight_data_exporter.py

@@ -3,6 +3,7 @@
 """
 
 import json
+import warnings
 
 import numpy as np
 import simplekml
@@ -89,16 +90,27 @@ class attributes which are instances of the Function class. Usage
 
         # Fast evaluation for the most basic scenario
         if time_step is None and len(variables) == 0:
+            warnings.warn(
+                "Exporting with no variables writes the full 14-column "
+                "canonical state table and will require explicit variable names "
+                "in v1.14. Pass the variable names you want, e.g. "
+                "data(file_name, 'x', 'y', 'z').",
+                DeprecationWarning,
+                stacklevel=2,
+            )
             np.savetxt(
                 file_name,
-                f.solution,
+                f.solution.canonical_array,
                 fmt="%.6f",
                 delimiter=",",
                 header=""
                 "Time (s),"
                 "X (m),"
                 "Y (m),"
                 "Z (m),"
+                "Vx (m/s),"
+                "Vy (m/s),"
+                "Vz (m/s),"
                 "E0,"
                 "E1,"
                 "E2,"