refactor: remove code that no production path reaches

These were all scaffolding that drifted out of use, and each one costs
a reader time before they discover it does nothing:

- UUIDASStringSerializer duplicated UUIDSerializer byte for byte; the
  differing descriptor name never reaches the JSON/YAML wire format, so
  the choice between them was a coin flip for contributors.
- Velocity's BuildInfo was never referenced (the plugin reads its version
  from PluginContainer) and read a "commit" property the build never
  wrote, so it would have reported "unknown" had anyone called it.
- KanaConverter.TrieNode.Leaf is never constructed: buildTrie starts from
  a Branch and insert only ever returns Branch. Six branches guarded
  against a state the type system allowed but the code could not produce.
  With those gone, isValidRomaji and toHiragana were visibly the same
  trie walk, so they now share one longestMatch.
- @Deprecated command handling had no annotated command to act on.
- The settings backup restore looked for *.backup.* files that nothing in
  the repository writes, so it always fell through to empty settings.

Also drops CommandContext.replyWithEvent/replyPlain, PluginCoroutineScope's
unused plugin parameter, GitHubRelease fields no caller reads, and four
language keys with no lookup site.

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

1 files changed, 0 insertions, 44 deletions

diff --git a/engine/src/test/kotlin/dev/m1sk9/lunaticChat/engine/settings/UUIDSerializerTest.kt b/engine/src/test/kotlin/dev/m1sk9/lunaticChat/engine/settings/UUIDSerializerTest.kt
index 599a372..58d9c32 100644
--- a/engine/src/test/kotlin/dev/m1sk9/lunaticChat/engine/settings/UUIDSerializerTest.kt
+++ b/engine/src/test/kotlin/dev/m1sk9/lunaticChat/engine/settings/UUIDSerializerTest.kt
@@ -16,12 +16,6 @@ class UUIDSerializerTest {
         val uuid: UUID,
     )
 
-    @Serializable
-    private data class UUIDAsStringHolder(
-        @Serializable(with = UUIDASStringSerializer::class)
-        val uuid: UUID,
-    )
-
     @Test
     fun `UUIDSerializer should serialize UUID to string`() {
         val uuid = UUID.fromString("12345678-1234-1234-1234-123456789abc")
@@ -52,35 +46,6 @@ class UUIDSerializerTest {
     }
 
     @Test
-    fun `UUIDASStringSerializer should serialize UUID to string`() {
-        val uuid = UUID.fromString("abcdef01-2345-6789-abcd-ef0123456789")
-        val holder = UUIDAsStringHolder(uuid)
-
-        val jsonString = json.encodeToString(UUIDAsStringHolder.serializer(), holder)
-
-        assert(jsonString.contains("abcdef01-2345-6789-abcd-ef0123456789"))
-    }
-
-    @Test
-    fun `UUIDASStringSerializer should deserialize string to UUID`() {
-        val jsonString = """{"uuid":"abcdef01-2345-6789-abcd-ef0123456789"}"""
-        val holder = json.decodeFromString(UUIDAsStringHolder.serializer(), jsonString)
-
-        assertEquals(UUID.fromString("abcdef01-2345-6789-abcd-ef0123456789"), holder.uuid)
-    }
-
-    @Test
-    fun `UUIDASStringSerializer round-trip should preserve UUID`() {
-        val originalUuid = UUID.randomUUID()
-        val holder = UUIDAsStringHolder(originalUuid)
-
-        val jsonString = json.encodeToString(UUIDAsStringHolder.serializer(), holder)
-        val decoded = json.decodeFromString(UUIDAsStringHolder.serializer(), jsonString)
-
-        assertEquals(originalUuid, decoded.uuid)
-    }
-
-    @Test
     fun `UUIDSerializer should fail on invalid UUID string`() {
         val jsonString = """{"uuid":"not-a-valid-uuid"}"""
 
@@ -88,13 +53,4 @@ class UUIDSerializerTest {
             json.decodeFromString(UUIDHolder.serializer(), jsonString)
         }
     }
-
-    @Test
-    fun `UUIDASStringSerializer should fail on invalid UUID string`() {
-        val jsonString = """{"uuid":"not-a-valid-uuid"}"""
-
-        assertFailsWith<Exception> {
-            json.decodeFromString(UUIDAsStringHolder.serializer(), jsonString)
-        }
-    }
 }