Phase 2 (Fundament): proportionale Teilverkauf-Logik pure + getestet

- SellLogic.SharesToSell (pure): spiegelt die Verkaufsquote des Masters. 0 =
  ignorieren (< MinSellRatioPct = Rauschen), = ourShares = Voll-Exit (Master ganz
  raus oder Rest/Teil unter Polymarket-Minimum -> kein Dust), sonst proportional.
- 7 Tests (Teilverkauf, Rausch-Schwelle, Voll-Exit-Faelle, Dust-Grenzen).

Wiring in die Engine bewusst zurueckgestellt: braucht Partial-Fill-Handling
(Phase 1.1 CLOB User-Channel, API-abhaengig -> Zielland). Aktuelles Voll-Exit-
Verhalten unveraendert.

200 Tests gruen. Build gruen.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/PolyTrader.Tests/SellLogicTests.cs

@@ -111,6 +111,53 @@ namespace PolyTrader.Tests
             Assert.False(IsProfitTargetReached(0.9m, 0m, 10m));
         }
 
+        // ---------------- SharesToSell (Phase 2) ----------------
+
+        [Fact]
+        public void SharesToSell_mirrors_partial_ratio()
+        {
+            // 40 % von 100, Rest 60 -> Teilverkauf 40
+            Assert.Equal(40m, SharesToSell(ourShares: 100m, sellRatio: 0.40m, minShares: 5.5m, minSellRatioPct: 10m));
+        }
+
+        [Fact]
+        public void SharesToSell_ignores_noise_below_min_ratio()
+        {
+            Assert.Equal(0m, SharesToSell(100m, 0.05m, 5.5m, 10m));
+        }
+
+        [Fact]
+        public void SharesToSell_full_exit_when_master_fully_out()
+        {
+            Assert.Equal(100m, SharesToSell(100m, 1.0m, 5.5m, 10m));
+        }
+
+        [Fact]
+        public void SharesToSell_full_exit_when_partial_would_be_dust()
+        {
+            // 30 % von 10 = 3 Shares < Minimum -> Voll-Exit
+            Assert.Equal(10m, SharesToSell(10m, 0.30m, 5.5m, 10m));
+        }
+
+        [Fact]
+        public void SharesToSell_full_exit_when_remainder_would_be_dust()
+        {
+            // 98 % von 100 -> Rest 2 < Minimum -> Voll-Exit
+            Assert.Equal(100m, SharesToSell(100m, 0.98m, 5.5m, 10m));
+        }
+
+        [Fact]
+        public void SharesToSell_zero_position_is_zero()
+        {
+            Assert.Equal(0m, SharesToSell(0m, 0.5m, 5.5m, 10m));
+        }
+
+        [Fact]
+        public void SharesToSell_exactly_at_min_ratio_is_not_ignored()
+        {
+            Assert.Equal(10m, SharesToSell(100m, 0.10m, 5.5m, 10m));
+        }
+
         [Fact]
         public void Ladder_walks_down_in_steps_until_floor()
         {