South Africa's mining stocks, once the engine behind a record rally, have flipped into the JSE's biggest drag, pushing the All Share Index to a 3.6% quarterly decline — its worst in nearly three years. Precious-metal prices have slumped since the Iran war as a hawkish Fed strengthened the dollar, hammering heavyweights like Gold Fields and AngloGold Ashanti. Despite this, valuations look increasingly attractive relative to emerging-market peers,…