=== Pure QSettings benchmark (100000 iterations) ===

--- Construction overhead ---

  QSettings() IniFormat ctor+dtor     =   11754 ns
  QSettings(path, Ini) ctor+dtor      =    2244 ns

--- Single read (reused instance) ---

  Scenario                                  QSettings      QHash
  ---------------------------------------------------------------
  Read user key                                90 ns     11 ns
  Read global key                              96 ns     14 ns

--- Single read (NEW instance each call) ---

  Scenario                                  QSettings      QHash
  ---------------------------------------------------------------
  Read user key                             11663 ns     11 ns

--- Thread-local singleton read ---

  thread_local QSettings* read                 90 ns

--- Realistic: 100 reads × 1000 rounds ---

  QSettings (new each)   × 1000:   1163.9 ms
  QSettings (reused)     × 1000:     28.4 ms
  thread_local singleton × 1000:     29.9 ms
  QHash only             × 1000:     17.1 ms