Add tutorial READMEs and fix tutorial return codes

Add README.md files for moeo/tutorial/Lesson{1-4}, smp/tutorial/Lesson{1-4},
and mo/tutorial/Lesson9 — these tutorials had no documentation.

Fix return 1 → return 0 in 28 tutorial main() functions across mo/ and
smp/ that unconditionally returned failure status.

moeo/tutorial/Lesson4/README.md

@@ -0,0 +1,35 @@
+# Dominance-based multi-objective local search (DMLS)
+
+Same flow-shop problem as Lessons 2-3, but solved with local search instead
+of an evolutionary algorithm. This combines ParadisEO-MO local search
+components with the MOEO multi-objective framework.
+
+## Running
+
+From the `build/moeo/tutorial/Lesson4` directory:
+
+```shell
+./FlowShopDMLS @FlowShopDMLS.param
+```
+
+## How it works
+
+The program uses `moShiftNeighbor` and `moOrderNeighborhood` from
+ParadisEO-MO, with `moeoFullEvalByCopy` to adapt the full solution
+evaluator for neighbor evaluation:
+
+```c++
+typedef moShiftNeighbor<FlowShop, FlowShopObjectiveVector> Neighbor;
+
+moOrderNeighborhood<Neighbor> neighborhood((nhSize-1) * (nhSize-1));
+moeoFullEvalByCopy<Neighbor> moEval(eval);
+```
+
+At each iteration, DMLS explores all non-dominated solutions in the
+archive via local search moves and updates the archive with any improving
+neighbors:
+
+```c++
+moeoFirstImprovingNeighborhoodExplorer<Neighbor> explor(neighborhood, moEval);
+moeoUnifiedDominanceBasedLS<Neighbor> algo(checkpoint, eval, arch, explor, select);
+```