feat(harness): the project map draws the groups the rail already has [SAP-2983]

.changeset/project-map-groups.md

@@ -0,0 +1,30 @@
+---
+"@sapiom/harness": minor
+---
+
+Studio: the project map draws your groups as named containers, instead of one
+endless column of agents.
+
+A project map used to draw every agent it contained as one flat set, ignoring
+the structure the rail was showing right beside it. Open a folder holding
+several systems and you got a single vertical column — a folder holding a few
+dozen agents came out thousands of pixels tall and one card wide, which no
+amount of zooming out makes readable.
+
+- **One labelled container per group.** The map now reads the same groups the
+  rail does, so a system you named in the rail is a system you can see on the
+  map, under exactly that name and in the same order. Rename or regroup in the
+  rail and the map follows immediately.
+- **Ungrouped is a container too.** "No connections detected" is a real answer
+  about a project, not an absence, so it gets a labelled box rather than being
+  scattered loose. A project with one group renders as one group.
+- **Agents with no connections wrap instead of stacking.** Inside a container,
+  unconnected agents fill the width and wrap, which is what replaces the column.
+- **A connector between two containers is still drawn.** Splitting a system
+  across two groups does not make the link between the halves disappear; it is
+  drawn dotted, as a link between systems rather than wiring inside one.
+- Container names stay readable as you zoom out, which is the moment you are
+  looking at the whole project and need to know which system is which.
+
+Nothing about how groups are detected, edited, or stored has changed. The map is
+a new reader of the arrangement your project already has; it never writes one.