feat(repomap): index C#/Godot-Mono (.cs) type symbols

Conservative type-declaration pattern (class/interface/struct/enum/record);
no method capture to avoid false positives. (BACKLOG I)

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

apps/server/src/main/kotlin/com/correx/apps/server/memory/RepoMapIndexer.kt

@@ -84,6 +84,12 @@ class RepoMapIndexer(
             "ts" to Regex("""(?m)^\s*(?:export\s+)?(?:default\s+)?(?:async\s+)?(?:function|class|interface|type|enum)\s+(?<name>[A-Za-z_$][A-Za-z0-9_$]*)"""),
             // GDScript: column-0 declarations only, so indented inner-class members never match.
             "gd" to Regex("""(?m)^(?:static\s+)?(?:func|class_name|class|signal|enum)\s+(?<name>[A-Za-z_][A-Za-z0-9_]*)"""),
+            // C# / Godot Mono: top-level type declarations with leading modifiers, kept conservative
+            // (no method capture — return-type heuristics there are noisy and risk false positives).
+            "cs" to Regex(
+                """(?m)^\s*(?:public |private |protected |internal |static |sealed |abstract |""" +
+                    """partial )*(?:class|interface|struct|enum|record)\s+(?<name>[A-Za-z_][A-Za-z0-9_]*)""",
+            ),
             // Markdown: h1–h3 headings as "symbols" — deeper levels are noise relative to retrieval value.
             "md" to Regex("""(?m)^#{1,3}\s+(?<name>.+?)\s*$"""),
         )

apps/server/src/test/kotlin/com/correx/apps/server/memory/RepoMapIndexerTest.kt

@@ -75,6 +75,42 @@ class RepoMapIndexerTest {
         assertFalse(entry.symbols.contains("help"), "indented inner method must not be matched")
     }
 
+    @Test
+    fun `extracts C# (Godot Mono) top-level type symbols`(@TempDir root: Path) {
+        root.resolve("Player.cs").writeText(
+            """
+            using Godot;
+
+            namespace Game;
+
+            public sealed partial class Player : CharacterBody2D
+            {
+                private int _health = 100;
+
+                public void TakeDamage(int amount)
+                {
+                    _health -= amount;
+                }
+            }
+
+            internal interface IDamageable
+            {
+                void TakeDamage(int amount);
+            }
+
+            public enum State { Idle, Running }
+            """.trimIndent(),
+        )
+
+        val entry = RepoMapIndexer().index(root).single()
+        assertEquals("Player.cs", entry.path)
+        assertTrue(
+            entry.symbols.containsAll(listOf("Player", "IDamageable", "State")),
+            "missing symbols in: ${entry.symbols}",
+        )
+        assertFalse(entry.symbols.contains("TakeDamage"), "method/field bodies must not be matched")
+    }
+
     @Test
     fun `extracts markdown headings as symbols`(@TempDir root: Path) {
         root.resolve("design.md").writeText(