fix: review fixes for SteinerTree — CLI help, re-exports, error message

- Add SteinerTree to CLI help table in cli.rs
- Add SteinerTree to random generation supported list in create.rs
- Add SteinerTree to models/mod.rs re-export
- Add SteinerTree to graph/mod.rs doc comment

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: zazabap

problemreductions-cli/src/cli.rs

@@ -215,6 +215,7 @@ Flags by problem type:
   MinimumSetCovering              --universe, --sets [--weights]
   BicliqueCover                   --left, --right, --biedges, --k
   BMF                             --matrix (0/1), --rank
+  SteinerTree                     --graph, --edge-weights, --terminals
   CVP                             --basis, --target-vec [--bounds]
   ILP, CircuitSAT                 (via reduction only)
 

problemreductions-cli/src/commands/create.rs

@@ -978,7 +978,7 @@ fn create_random(
         _ => bail!(
             "Random generation is not supported for {canonical}. \
              Supported: graph-based problems (MIS, MVC, MaxCut, MaxClique, \
-             MaximumMatching, MinimumDominatingSet, SpinGlass, KColoring, TravelingSalesman)"
+             MaximumMatching, MinimumDominatingSet, SpinGlass, KColoring, TravelingSalesman, SteinerTree)"
         ),
     };
 

src/models/graph/mod.rs

@@ -10,6 +10,7 @@
 //! - [`KColoring`]: K-vertex coloring
 //! - [`MaximumMatching`]: Maximum weight matching
 //! - [`TravelingSalesman`]: Traveling Salesman (minimum weight Hamiltonian cycle)
+//! - [`SteinerTree`]: Steiner Tree (minimum weight tree connecting terminals)
 //! - [`SpinGlass`]: Ising model Hamiltonian
 //! - [`BicliqueCover`]: Biclique cover on bipartite graphs
 

src/models/mod.rs

@@ -13,7 +13,8 @@ pub use algebraic::{ClosestVectorProblem, BMF, ILP, QUBO};
 pub use formula::{CNFClause, CircuitSAT, KSatisfiability, Satisfiability};
 pub use graph::{
     BicliqueCover, KColoring, MaxCut, MaximalIS, MaximumClique, MaximumIndependentSet,
-    MaximumMatching, MinimumDominatingSet, MinimumVertexCover, SpinGlass, TravelingSalesman,
+    MaximumMatching, MinimumDominatingSet, MinimumVertexCover, SpinGlass, SteinerTree,
+    TravelingSalesman,
 };
 pub use misc::{BinPacking, Factoring, PaintShop};
 pub use set::{MaximumSetPacking, MinimumSetCovering};