Dim command row address, fix source picker zoom/styling, lowercase menu items, margin spacing

- Apply IND_HEX_DIM to base address on command row so it matches source/struct grey
- Source picker QMenu respects Scintilla zoom level for font size
- Style source picker with dark theme selection color instead of system blue
- Disable blue selection background for picker-based edit targets (Source, Type, etc.)
- Rename menu items File/Process to file/process
- Add trailing space to margin offset text for breathing room

src/format.cpp

@@ -112,8 +112,8 @@ QString indent(int depth) {
 // ── Offset margin ──
 
 QString fmtOffsetMargin(uint64_t absoluteOffset, bool isContinuation) {
-    if (isContinuation) return QStringLiteral("  \u00B7");
-    return QString::number(absoluteOffset, 16).toUpper();
+    if (isContinuation) return QStringLiteral("  \u00B7 ");
+    return QString::number(absoluteOffset, 16).toUpper() + QChar(' ');
 }
 
 // ── Struct type name (for width calculation) ──