KindFlags refactor, indicator helpers, auto-padding, sizeof format fix

- Add KindFlags bitmask enum (KF_HexPreview, KF_Container, KF_String, KF_Vector)
- Add helper functions: isHexPreview(), flagsFor(), allTypeNamesForUI()
- Add editor helpers: clearIndicatorLine(), fillIndicatorCols(), resolvedSpanFor()
- Use SCI_FINDCOLUMN for UTF-8 safe column-to-position conversion
- Auto-emit hex padding nodes when changing type to smaller size
- Fix struct footer format: sizeof(Name)=0x... (no spaces)
- Add tests for sizeof recalculation after node deletion
- Add debug output to investigate sizeof refresh issue
- Replace icons.qrc with resources.qrc, add embedded fonts

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/compose.cpp

@@ -192,7 +192,7 @@ void composeParent(ComposeState& state, const NodeTree& tree,
         lm.nodeKind   = node.kind;
         lm.offsetText = QStringLiteral("  ---");
         lm.foldLevel  = computeFoldLevel(depth, false);
-        lm.markerMask = (1u << M_STRUCT_BG);
+        lm.markerMask = 0;
         int sz = tree.structSpan(node.id, &state.childMap);
         state.emitLine(fmt::fmtStructFooter(node, depth, sz), lm);
     }