fix: WinDbg provider stops auto-selecting module, new tabs inherit source

- WinDbg provider no longer picks arbitrary module[0] as name/base
  (was showing "WS2_32" for kernel dumps). Name is now generic
  "WinDbg (Live)" / "WinDbg (Dump)", base stays 0 so controller
  doesn't override user's address.
- Added throttled read failure logging to WinDbg provider.
- New tabs (File→New Class, workspace right-click) inherit the
  current tab's source/provider so users don't have to re-attach.
- Updated WinDbg provider tests for new behavior.

src/controller.h

@@ -131,6 +131,7 @@ public:
     void switchSource(int idx) { switchToSavedSource(idx); }
     void clearSources();
     void selectSource(const QString& text);
+    void copySavedSources(const QVector<SavedSourceEntry>& sources, int activeIdx);
 
     // Value tracking toggle (per-tab, off by default)
     bool trackValues() const { return m_trackValues; }