feat(editor): type-checked connections + card-height fix + widget tests

Three changes:

1. Type-checked port connections. Drag from an output port
   only highlights compatible-type input ports as drop
   targets; incompatible drops are silently refused. Source
   of truth: ModuleSpec for declared types. When either side
   is unknown (no manifest, implicit YAML field) the check
   degrades to 'compatible with anything' so a missing
   manifest never blocks composition.

2. NodeGeometry.heightFor now adds a 2 px allowance for the
   1 px AnimatedContainer border on top + bottom of the
   card. Without this the last port-row's Column would
   overflow by 2 px under tight layout constraints (caught
   by the new widget tests; production canvas clipped it
   silently inside InteractiveViewer).

3. Width parameter on FlowNode now actually drives the
   outer SizedBox. The dynamic _stepWidth value from the
   canvas finally reaches the card border rather than being
   shadowed by NodeGeometry.width. Long labels
   (model_endpoint, source_language) no longer ellipsis-clip.

Tests: 8 new widget + geometry tests covering width growth,
two-column body layout, port-tooltip attachment,
row-alignment between input and output sides, and the
existing kindForStep classifier. All 20 editor tests pass.

Bumps fai_studio_flow_editor to 0.11.0.

Signed-off-by: flemming-it <sf@flemming.it>

lib/src/widgets/flow_node.dart

@@ -94,10 +94,18 @@ class NodeGeometry {
   /// Total card height for a node carrying [inputCount] inputs
   /// on the left + [outputCount] outputs on the right. The
   /// taller side wins; the card always reserves at least one
-  /// row of body so the header doesn't sit naked.
+  /// row of body so the header doesn't sit naked. Adds a
+  /// 2 px allowance for the 1 px border on the top + bottom
+  /// of the AnimatedContainer wrapping the card, otherwise
+  /// the inner Column gets shorted by the border and the
+  /// last port row overflows.
   static double heightFor(int inputCount, [int outputCount = 0]) {
     final rows = inputCount > outputCount ? inputCount : outputCount;
-    return headerHeight + bodyTopPad + rows * portRowHeight + bodyBottomPad;
+    return headerHeight +
+        bodyTopPad +
+        rows * portRowHeight +
+        bodyBottomPad +
+        2;
   }
 
   /// Y offset (from the card's top edge) where the input
@@ -290,11 +298,7 @@ class FlowNode extends StatelessWidget {
         ),
       );
     }
-    return SizedBox(
-      width: NodeGeometry.width,
-      height: height,
-      child: cardWidget,
-    );
+    return SizedBox(width: width, height: height, child: cardWidget);
   }
 
   Widget _card(ThemeData theme, Color accent, double height) {