feat: enable initial-consonant search everywhere

tests/MBN_STOCK_WEBVIEW.LegacyApplication.Tests/LegacyThemeWorkflowTests.cs

@@ -366,6 +366,62 @@ public sealed class LegacyThemeWorkflowTests
         Assert.Equal("theme-result-5000", snapshot.SearchResults[^1].ResultId);
     }
 
+    [Fact]
+    public async Task SearchAsync_AcceptsConservativeTruncationAfterInitialFiltering()
+    {
+        var service = new FakeThemeSelectionService
+        {
+            SearchHandler = (query, session) => new ThemeSearchResult(
+                query,
+                session,
+                DateTimeOffset.UtcNow,
+                [
+                    Selector(
+                        ThemeMarket.Krx,
+                        ThemeSession.NotApplicable,
+                        "삼성 테마",
+                        "00000001")
+                ],
+                IsTruncated: true)
+        };
+        var workflow = new LegacyThemeWorkflow(service);
+
+        var snapshot = await workflow.SearchAsync(
+            workflow.CreateInitial(),
+            "ㅅㅅ",
+            ThemeSession.PreMarket);
+
+        Assert.Equal("삼성 테마", Assert.Single(snapshot.SearchResults).DisplayTitle);
+        Assert.True(snapshot.SearchIsTruncated);
+    }
+
+    [Fact]
+    public async Task SearchAsync_StillRejectsImpossiblePartialTruncationForOrdinaryText()
+    {
+        var service = new FakeThemeSelectionService
+        {
+            SearchHandler = (query, session) => new ThemeSearchResult(
+                query,
+                session,
+                DateTimeOffset.UtcNow,
+                [
+                    Selector(
+                        ThemeMarket.Krx,
+                        ThemeSession.NotApplicable,
+                        "AI",
+                        "00000001")
+                ],
+                IsTruncated: true)
+        };
+        var workflow = new LegacyThemeWorkflow(service);
+
+        await Assert.ThrowsAsync<LegacyThemeWorkflowDataException>(() =>
+            workflow.SearchAsync(
+                workflow.CreateInitial(),
+                "AI",
+                ThemeSession.PreMarket));
+    }
+
     [Fact]
     public async Task SelectAsync_UsesOpaqueResultIdAndCopiesValidatedPreview()
     {