fix(config-sheet): EnumControl always uses Menu picker, never Segmented

The Configuration sheet's clipping bug persisted after the earlier
VStack maxWidth fix (d616935) and the user's Part-C manifest
rewrite to use [label](url) markdown. Re-diagnosed: the actual
overflow source was EnumControl's `.pickerStyle(.segmented)` branch,
active when options.count ≤ 4.

Segmented pickers on macOS size to the intrinsic width of all their
labels concatenated. They refuse offered width constraints, refuse
to wrap, refuse to truncate. A schema with three long labels like
"Claude Opus 4 (Recommended - Most Capable)" produced a ~650pt
segmented picker that pushed the fieldRow past the sheet's 560pt
viewport. No amount of .frame(maxWidth: .infinity) on parent
containers can rein in a segmented picker — the picker ignores
them.

Fix: remove the segmented branch. Always use the default Menu
picker (dropdown). Dropdowns respect offered width and surface long
labels in the popup list, so the sheet can't overflow regardless of
label length or option count.

Loses the segmented look for short-enum cases like a 3-option
"Daily / Weekly / Monthly" picker — compactness traded for
correctness. If a future template author wants segmented rendering
for a specific short-label enum, we can add a manifest hint
(e.g., "uiHint": "segmented") that explicitly opts in; not worth
the machinery until there's demand.

58/58 Swift tests still pass. No schema changes, no migration.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scarf/scarf/Features/Templates/Views/TemplateConfigSheet.swift

@@ -312,17 +312,17 @@ private struct EnumControl: View {
     let options: [TemplateConfigField.EnumOption]
     @Binding var value: String
     var body: some View {
-        // Segmented for ≤ 4 options, dropdown otherwise — fits Scarf's
-        // existing settings UI.
-        if options.count <= 4 {
-            Picker("", selection: $value) {
-                ForEach(options) { opt in
-                    Text(opt.label).tag(opt.value)
-                }
-            }
-            .pickerStyle(.segmented)
-            .labelsHidden()
-        } else {
+        // Always use the default Menu picker (dropdown). An earlier
+        // version switched to `.pickerStyle(.segmented)` when
+        // `options.count ≤ 4` for a more compact look, but on macOS
+        // segmented pickers size to the intrinsic width of all their
+        // labels concatenated — they refuse offered width constraints
+        // and refuse to wrap. A schema with three long labels like
+        // "Claude Opus 4 (Recommended - Most Capable)" produced a
+        // ~650pt picker that overflowed the 560pt sheet viewport,
+        // clipping the entire form. Menu pickers respect the fieldRow's
+        // offered width and show long labels in the popup list, so the
+        // sheet can't overflow regardless of label length.
         Picker("", selection: $value) {
             ForEach(options) { opt in
                 Text(opt.label).tag(opt.value)
@@ -330,7 +330,6 @@ private struct EnumControl: View {
         }
         .labelsHidden()
     }
-    }
 }
 
 /// Variable-length list of string values. Each row is a text field