Show complete user credit data in admin

Load users by registration order, expose consumed and current credits, and accept short internal IDs so support can reliably locate accounts.

src/test/kotlin/com/osglab/account/features/admin/users/AdminUsersServiceTest.kt

@@ -143,6 +143,40 @@ class AdminUsersServiceTest : FunSpec({
         }
     }
 
+    test("search accepts an uppercase 8-character internal user ID suffix") {
+        val matchingId = UUID.fromString("11111111-1111-4111-8111-aaaae3c7c475")
+        val otherId = UUID.fromString("22222222-2222-4222-8222-bbbb12345678")
+        val service = AdminUsersService(
+            PagingUsersRepository(
+                listOf(
+                    summary(matchingId, Instant.parse("2026-08-15T02:00:00Z")),
+                    summary(otherId, Instant.parse("2026-08-15T01:00:00Z")),
+                ),
+            ),
+        )
+
+        val page = service.searchByInternalId("E3C7C475")
+
+        page.items.map { it.id } shouldBe listOf(matchingId.toString())
+        page.nextCursor shouldBe null
+    }
+
+    test("short ID search returns all collisions for disambiguation") {
+        val firstId = UUID.fromString("11111111-1111-4111-8111-aaaae3c7c475")
+        val secondId = UUID.fromString("22222222-2222-4222-8222-bbbbe3c7c475")
+        val service = AdminUsersService(
+            PagingUsersRepository(
+                listOf(
+                    summary(firstId, Instant.parse("2026-08-15T02:00:00Z")),
+                    summary(secondId, Instant.parse("2026-08-15T01:00:00Z")),
+                ),
+            ),
+        )
+
+        service.searchByInternalId("e3c7c475").items.map { it.id } shouldBe
+            listOf(firstId.toString(), secondId.toString())
+    }
+
     test("invalid user cursor and missing detail fail without returning user data") {
         val service = AdminUsersService(PagingUsersRepository(emptyList()))
 
@@ -178,6 +212,12 @@ private class PagingUsersRepository(
         ledgerLimit: Int,
     ): AdminUserDetailDto? = details[userId]
 
+    override suspend fun findByIdSuffix(
+        suffix: String,
+        limit: Int,
+    ): List<AdminUserSummaryDto> =
+        users.filter { it.id.endsWith(suffix, ignoreCase = true) }.take(limit)
+
     override suspend fun exists(userId: UUID): Boolean =
         userId in details || userId in ledger || users.any { it.id == userId.toString() }