Starter economy: stronger low-end cards; handbook: withdrawal screening rules and wallet destroy; revert wallet-destroy guard

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/Decentralized.Domain/Mining.cs

@@ -38,9 +38,9 @@ namespace Decentralized.Domain
         public static readonly IReadOnlyDictionary<string, HardwareSpec> Specs = new[]
         {
             // 四个档次（低端、中端、高端、旗舰），两个牌子通用：型号只是显示名，性能和价格由「牌子 + 档次」决定
-            Gpu("RTX60", Probidia, 0, 1.0, 4, 220), Gpu("RTX70", Probidia, 1, 5.0, 12, 800),
+            Gpu("RTX60", Probidia, 0, 1.8, 4, 220), Gpu("RTX70", Probidia, 1, 5.0, 12, 800),
             Gpu("RTX80", Probidia, 2, 8.0, 18, 1300), Gpu("RTX90", Probidia, 3, 20.0, 30, 5000),
-            Gpu("RX70", Pmd, 0, 0.8, 2.5, 170), Gpu("RX80", Pmd, 1, 4.0, 8, 680),
+            Gpu("RX70", Pmd, 0, 1.4, 2.5, 170), Gpu("RX80", Pmd, 1, 4.0, 8, 680),
             Gpu("RX800", Pmd, 2, 8.0, 14, 1500), Gpu("RX900", Pmd, 3, 15.0, 20, 4000),
             Scrap("RX10", Pmd, 0, 0.3, 2, 60),
             Asic("M1", 50, 60, 11000), Asic("M2", 120, 110, 27000), Asic("M3", 300, 220, 72000),