feat: primitive pointer modifiers, type chooser fixes, double-click to edit

Type chooser:
- Fix PointerTarget mode hiding primitives due to stale modifier state
- Preselect */[n] modifier buttons to reflect current node type
- Primitive pointer support: int32*, double**, etc with provider deref
- hex64*/ptr64* with * modifier falls back to void* (meaningless deref)
- isValidPrimitivePtrTarget guard in controller, compose, format
- Modifier toggle no longer resets list selection
- Primitive pointers open FieldType mode (not PointerTarget)
- Type edit requires double-click (was single-click, too easy to misclick)

Other:
- Custom dock titlebar with themed close button, no float button
- Status bar font synced at startup
- Resize grip reworked as direct MainWindow child, font-independent
- File menu "Source" renamed to "Current Tab Source"

Tests: 41 type_selector, 39 editor, 17 controller (200 total, 0 failures)

src/compose.cpp

@@ -119,8 +119,17 @@ void composeLeaf(ComposeState& state, const NodeTree& tree,
     QString ptrTypeOverride;
     QString ptrTargetName;
     if (node.kind == NodeKind::Pointer32 || node.kind == NodeKind::Pointer64) {
-        ptrTargetName = resolvePointerTarget(tree, node.refId);
-        ptrTypeOverride = fmt::pointerTypeName(node.kind, ptrTargetName);
+        if (node.ptrDepth > 0 && isValidPrimitivePtrTarget(node.elementKind)) {
+            // Primitive pointer: e.g. "int32*" or "f64**"
+            const auto* meta = kindMeta(node.elementKind);
+            QString baseName = meta ? QString::fromLatin1(meta->typeName)
+                                    : QStringLiteral("void");
+            QString stars = (node.ptrDepth >= 2) ? QStringLiteral("**") : QStringLiteral("*");
+            ptrTypeOverride = baseName + stars;
+        } else {
+            ptrTargetName = resolvePointerTarget(tree, node.refId);
+            ptrTypeOverride = fmt::pointerTypeName(node.kind, ptrTargetName);
+        }
     }
 
     for (int sub = 0; sub < numLines; sub++) {