Show latest credit ledger in admin

Expose a paginated global ledger timeline and load it automatically so operators can see recent credit activity without first locating a user.

src/test/kotlin/com/osglab/account/config/DeploymentConsistencyTest.kt

@@ -84,10 +84,14 @@ class DeploymentConsistencyTest : FunSpec({
         val referralMigration = root.read(
             "src/main/resources/db/migration/V12__align_referral_rewards.sql",
         )
+        val ledgerTimelineMigration = root.read(
+            "src/main/resources/db/migration/V13__credit_ledger_global_timeline.sql",
+        )
         profileMigration shouldContain "encrypted_display_name MEDIUMTEXT NOT NULL"
         profileMigration shouldContain "REFERENCES accounts (id) ON DELETE CASCADE"
         referralMigration shouldContain "inviter_reward_credits = 1000"
         referralMigration shouldContain "invitee_reward_credits = 1000"
+        ledgerTimelineMigration shouldContain "ON credit_ledger (created_at, id)"
 
         listOf(
             root.read("src/main/resources/application.yaml"),
@@ -234,6 +238,7 @@ private val EXPECTED_PUBLIC_PATHS = setOf(
     "/v1/admin/users",
     "/v1/admin/users/{userId}",
     "/v1/admin/users/{userId}/ledger",
+    "/v1/admin/credits/ledger",
     "/v1/admin/credits/grants",
     "/v1/admin/operators/summary",
     "/v1/admin/operators",