revert: Remove 'numerical' termination condition, keep only 'imprecise'

Remove 'numerical' enum value and mapping from STATUS_TO_TERMINATION_CONDITION_MAP while preserving the 'imprecise' additions for COPT solver compatibility.

Co-authored-by: Fabian Hofmann <[email protected]>

Author: claude[bot]

linopy/constants.py

@@ -106,7 +106,6 @@ class TerminationCondition(Enum):
     iteration_limit = "iteration_limit"
     terminated_by_limit = "terminated_by_limit"
     suboptimal = "suboptimal"
-    numerical = "numerical"
     imprecise = "imprecise"
 
     # WARNING
@@ -143,7 +142,6 @@ def process(
         TerminationCondition.time_limit,
         TerminationCondition.terminated_by_limit,
         TerminationCondition.suboptimal,
-        TerminationCondition.numerical,
         TerminationCondition.imprecise,
     ],
     SolverStatus.warning: [