Add saved sources with quick-switch in source picker

Source picker now remembers loaded files and attached processes below a
separator with checkmarks. Clicking a saved source instantly switches
back to it, preserving base addresses per-source.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/editor.h

@@ -9,6 +9,11 @@ class QsciLexerCPP;
 
 namespace rcx {
 
+struct SavedSourceDisplay {
+    QString text;
+    bool active = false;
+};
+
 class RcxEditor : public QWidget {
     Q_OBJECT
 public:
@@ -45,6 +50,9 @@ public:
     // Custom type names (struct types from the tree) shown in type picker
     void setCustomTypeNames(const QStringList& names) { m_customTypeNames = names; }
 
+    // Saved sources for quick-switch in source picker
+    void setSavedSources(const QVector<SavedSourceDisplay>& sources) { m_savedSourceDisplay = sources; }
+
 signals:
     void marginClicked(int margin, int line, Qt::KeyboardModifiers mods);
     void contextMenuRequested(int line, int nodeIdx, int subLine, QPoint globalPos);
@@ -109,6 +117,9 @@ private:
     // ── Custom type names for type picker ──
     QStringList m_customTypeNames;
 
+    // ── Saved sources for quick-switch ──
+    QVector<SavedSourceDisplay> m_savedSourceDisplay;
+
     // ── Reentrancy guards ──
     bool m_clampingSelection = false;
     bool m_updatingComment = false;