fix(shard): decode in-game serials as hex strings, not numbers

The public shard board DTOs typed in-game serials (and actor webId) as
Long, but the wire protocol (docs/link/INTEGRATION.md §1) sends them as
opaque hex strings ("0x1A2B"). The website returns board payloads
verbatim, so a guild leader / champ / governor carrying a hex serial
threw JsonDecodingException out of the Retrofit converter and crashed the
app on the Guilds/Champs/Governors boards. The API is the source of
truth, so the DTOs are corrected to match it.

- ActorDto.serial/webId, ChampDto.serial, HouseDto.serial,
  OnlineStaffDto.serial: Long -> String
- champ.remove / house.decay live frames now read serial via stringField;
  longField returned null on a hex serial, silently dropping every board
  removal and live IDOC update
- safeApiCall now catches SerializationException -> ErrorKind.SERVER, so
  any future contract drift degrades to a retry-able error instead of a
  crash (defense in depth)
- DTO + result tests updated to the real hex-string wire shapes

AI-assisted: authored with Claude Code (Opus 4.8).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NgyHnrNa8WwG3doxvxjuCr

app/src/main/java/com/runicgateway/app/core/result/ApiResult.kt

@@ -4,6 +4,7 @@
 package com.runicgateway.app.core.result
 
 import kotlinx.coroutines.CancellationException
+import kotlinx.serialization.SerializationException
 import retrofit2.HttpException
 import java.io.IOException
 
@@ -37,6 +38,16 @@ inline fun <T, R> ApiResult<T>.map(transform: (T) -> R): ApiResult<R> = when (th
  * Run a suspending Retrofit call and normalize every outcome into an [ApiResult].
  * Coroutine cancellation is rethrown so structured concurrency still works — it
  * is control flow, not a network failure.
+ *
+ * A body the app can't decode (a field whose type/shape doesn't match its DTO, e.g.
+ * a live-shaped `guild.update` snapshot carrying an unexpected value) throws a
+ * [SerializationException] out of the Retrofit converter. That is a broken contract
+ * with the backend, not a bug to crash on: the request completed but the response is
+ * unusable — an invalid upstream response — so it is surfaced as a server-side error
+ * (`502` → [ErrorKind.SERVER]) the screen renders as "something went wrong, retry",
+ * exactly the graceful-degradation the layer promises (never throw for an expected
+ * failure). Without this catch the exception escapes the collecting coroutine and
+ * takes down the whole app.
  */
 suspend fun <T> safeApiCall(block: suspend () -> T): ApiResult<T> = try {
     ApiResult.Ok(block())
@@ -46,4 +57,9 @@ suspend fun <T> safeApiCall(block: suspend () -> T): ApiResult<T> = try {
     ApiResult.HttpError(e.code(), e.message())
 } catch (e: IOException) {
     ApiResult.NetworkError(e)
+} catch (e: SerializationException) {
+    ApiResult.HttpError(MALFORMED_RESPONSE_STATUS, e.message)
 }
+
+/** Synthetic status for a 2xx body the app couldn't decode — an invalid upstream response. */
+private const val MALFORMED_RESPONSE_STATUS = 502

app/src/main/java/com/runicgateway/app/data/api/dto/PlayerShardDto.kt

@@ -14,8 +14,8 @@ import kotlinx.serialization.json.JsonObject
  * `CharacterSheet.jsx` / `GameAccounts.jsx` and `docs/link/INTEGRATION.md` §5).
  * Presentation is text-only for v1 (no item icons / paperdoll).
  *
- * In-game serials are hex strings (e.g. "0x24C"), unlike the numeric serials on
+ * In-game serials are hex strings (e.g. "0x24C"), the same opaque-key form used on
- * the public boards — these are separate endpoints with separate shapes.
+ * the public boards (`ShardDto.ActorDto`/`ChampDto`/`HouseDto`) — never numbers.
  */
 
 // ── Game-account linking ─────────────────────────────────────────────────────

app/src/main/java/com/runicgateway/app/data/api/dto/ShardDto.kt

@@ -15,13 +15,18 @@ import kotlinx.serialization.json.JsonObject
  * `*.update` frames on `/public/shard/stream` decode into these same DTOs.
  */
 
-/** A game actor (player/leader/governor) as embedded in board payloads. */
+/**
+ * A game actor (player/leader/governor) as embedded in board payloads. Per the wire
+ * spec (`docs/link/INTEGRATION.md` §1), in-game [serial]s are opaque hex-string keys
+ * (e.g. `"0x1A2B"`), never numbers, and [webId] is the linked site-user id as a
+ * string (e.g. `"9931"`) — both are decoded as strings, not parsed.
+ */
 @Serializable
 data class ActorDto(
-    val serial: Long? = null,
+    val serial: String? = null,
     val name: String? = null,
     val acct: String? = null,
-    val webId: Long? = null,
+    val webId: String? = null,
 ) {
     /** Best display label for this actor. */
     val label: String get() = name ?: acct ?: "Someone"
@@ -73,7 +78,7 @@ data class FeedEventDto(
  */
 @Serializable
 data class OnlineStaffDto(
-    val serial: Long? = null,
+    val serial: String? = null,
     val name: String? = null,
     val map: String? = null,
     val x: Int? = null,
@@ -87,7 +92,7 @@ data class OnlineStaffDto(
  */
 @Serializable
 data class HouseDto(
-    val serial: Long = 0,
+    val serial: String = "",
     val name: String? = null,
     val region: String? = null,
     val map: String? = null,
@@ -104,7 +109,7 @@ data class HouseDto(
  */
 @Serializable
 data class ChampDto(
-    val serial: Long = 0,
+    val serial: String = "",
     val category: String? = null,
     val type: String? = null,
     val name: String? = null,

app/src/main/java/com/runicgateway/app/ui/shard/ChampsViewModel.kt

@@ -69,7 +69,9 @@ class ChampsViewModel @Inject constructor(
     private fun applyFrame(frame: ShardStreamEvent.Frame) {
         when (frame.kind) {
             "champ.update" -> repository.champFrame(frame.data)?.let { board.upsert(it) }
-            "champ.remove" -> FrameFields.longField(frame.data, "serial")?.let { board.remove(it.toString()) }
+            // Serial is an opaque hex-string key ("0x…"), not a number — read as a
+            // string (reading it as a Long silently dropped every champ.remove).
+            "champ.remove" -> FrameFields.stringField(frame.data, "serial")?.let { board.remove(it) }
             else -> return
         }
         // Only republish when the board actually changed (Success state only).

app/src/main/java/com/runicgateway/app/ui/shard/HousesViewModel.kt

@@ -69,7 +69,9 @@ class HousesViewModel @Inject constructor(
 
     private fun applyFrame(frame: ShardStreamEvent.Frame) {
         if (frame.kind != "house.decay") return
-        val serial = FrameFields.longField(frame.data, "serial") ?: return
+        // Serials are opaque hex-string keys ("0x…"), not numbers — read as a string
+        // (reading it as a Long silently dropped every live IDOC update).
+        val serial = FrameFields.stringField(frame.data, "serial") ?: return
         // `to` is the new decay stage; only IDOC belongs on the public board.
         val stage = FrameFields.stringField(frame.data, "to")
             ?: FrameFields.stringField(frame.data, "stage")

app/src/test/java/com/runicgateway/app/core/result/ApiResultTest.kt

@@ -35,6 +35,20 @@ class ApiResultTest {
         assertTrue(result is ApiResult.NetworkError)
     }
 
+    /**
+     * A body the app can't decode (a field whose type doesn't match its DTO) throws a
+     * [SerializationException] out of the Retrofit converter. It must degrade to a
+     * server-side error the UI renders, not escape and crash the app — the guild-board
+     * crash this fixes. `502` folds to [ui.ErrorKind.SERVER] via `toUiState`.
+     */
+    @Test fun serializationExceptionBecomesServerError() = runTest {
+        val result = safeApiCall {
+            throw kotlinx.serialization.SerializationException("Unexpected symbol 'm' at path: \$[0].members")
+        }
+        assertTrue(result is ApiResult.HttpError)
+        assertEquals(502, (result as ApiResult.HttpError).status)
+    }
+
     @Test fun cancellationIsRethrown() = runTest {
         assertThrows(CancellationException::class.java) {
             kotlinx.coroutines.runBlocking {

app/src/test/java/com/runicgateway/app/data/api/dto/ShardDtoTest.kt

@@ -43,25 +43,31 @@ class ShardDtoTest {
     }
 
     @Test fun champUpdateFrameDecodesWithKindAndExtras() {
-        // A live champ.update frame: has `kind`, `serial`, and category extras. The
+        // A live champ.update frame: has `kind`, a hex-string `serial` (INTEGRATION.md
-        // `kind` field is ignored (not on the DTO) and the extras decode.
+        // §1 — serials are opaque hex keys, never numbers), and category extras. The
+        // `kind`/`rank`/`autoRestart` fields are ignored (not on the DTO); extras decode.
         val dto = json.decodeFromString<ChampDto>(
-            """{"kind":"champ.update","serial":12345,"category":"champion","name":"Barracoon",
+            """{"kind":"champ.update","serial":"0x40012345","category":"champion","name":"Barracoon",
-               "status":"active","active":true,"level":10,"maxKills":250,"kills":120,
+               "status":"active","active":true,"level":10,"rank":3,"maxKills":250,"kills":120,
-               "bossUp":false,"map":"Felucca","x":5571,"y":1379,"z":0,"t":1721426400000}""",
+               "autoRestart":true,"bossUp":false,"map":"Felucca","x":5571,"y":1379,"z":0,"t":1721426400000}""",
         )
-        assertEquals(12345L, dto.serial)
+        assertEquals("0x40012345", dto.serial)
         assertEquals("champion", dto.category)
         assertEquals(120, dto.kills)
         assertTrue(dto.active)
     }
 
     @Test fun guildFrameDecodesLeaderActor() {
+        // The leader actor carries a hex-string serial and a string webId (the linked
+        // site-user id) — the exact wire shape from INTEGRATION.md §7.
         val dto = json.decodeFromString<GuildDto>(
             """{"kind":"guild.update","id":7,"name":"Knights","abbr":"KNT","members":12,
-               "online":3,"alliance":"Light","leader":{"serial":1,"name":"Arthur","acct":"art"}}""",
+               "online":3,"alliance":"Light",
+               "leader":{"serial":"0x1A2B","name":"Arthur","acct":"art","webId":"9931","player":true}}""",
         )
         assertEquals(7L, dto.id)
+        assertEquals("0x1A2B", dto.leader?.serial)
+        assertEquals("9931", dto.leader?.webId)
         assertEquals("Arthur", dto.leader?.label)
         assertEquals(12, dto.members)
     }
@@ -86,13 +92,21 @@ class ShardDtoTest {
 
     @Test fun houseDecodesPublicIdocShape() {
         val dto = json.decodeFromString<HouseDto>(
-            """{"serial":999,"name":"Tower","region":"Britain","map":"Felucca",
+            """{"serial":"0x40001234","name":"Tower","region":"Britain","map":"Felucca",
                "x":1,"y":2,"z":3,"isIdoc":true}""",
         )
-        assertEquals(999L, dto.serial)
+        assertEquals("0x40001234", dto.serial)
         assertTrue(dto.isIdoc)
     }
 
+    @Test fun onlineStaffDecodesHexSerial() {
+        val dto = json.decodeFromString<OnlineStaffDto>(
+            """{"serial":"0x24C","name":"Darrow"}""",
+        )
+        assertEquals("0x24C", dto.serial)
+        assertEquals("Darrow", dto.name)
+    }
+
     @Test fun actorLabelFallsBackToAcctThenSomeone() {
         assertEquals("bob", ActorDto(acct = "bob").label)
         assertEquals("Someone", ActorDto().label)