feat: consolidate player tracking in @dcl/sdk/players

The players helper gated arrivals on PlayerIdentityData AND AvatarBase, so a peer
whose avatar profile replicates late — or never — was never reported at all. Every
scene running an authoritative server therefore hand-rolled its own tracker:
diff PlayerIdentityData each frame, keep a Set of lowercased addresses, and poll
AvatarBase on a timer for the display name.

Rather than add a parallel API for that, this reworks the existing one.

onEnterScene/onLeaveScene keep their exact semantics and payloads by default, and
take an options object:

  onEnterScene(cb)                            // unchanged: identity + profile
  onEnterScene(cb, { requireProfile: false }) // as soon as the identity exists

Both thresholds come from one diff pass, so the sets cannot drift. Also new:
onPlayerNameChanged (replaces polling AvatarBase), getPlayers, getPlayerCount, a
never-empty displayName on the player payload, and nameResolved / joinedAtMs.
onLeaveScene gained a second argument carrying the last known state, since
getPlayer returns null once the entity is gone; extra callback parameters are
source-compatible, so existing one-argument handlers are unaffected.

Fixes found while reworking it, all of which affected client scenes too:

- `players.length === playerEntities.size` compared a count of entities against a
  map cleaned elsewhere; the two could coincide while the sets differed, silently
  dropping a join.
- Leaves were detected through AvatarBase.onChange, so a peer that lost identity
  without a profile change never fired onLeaveScene — and the per-entity onChange
  callbacks had no removal path, accumulating for the life of the process.
- Duplicate entities for one address resolved the name from whichever came first
  in insertion order, pinning the player to the stale entity forever. Now the one
  carrying a profile wins.
- A name starting with `0x` was treated as an address echo; `0xSomeName` is a
  legal claimed name. Compared against the actual address instead.
- isGuest was captured once and never refreshed.
- getPlayer compared addresses case-sensitively, so a lowercased address silently
  returned null.
- Callbacks had no unsubscribe and no error isolation: one throwing handler killed
  the tracker for the rest of the run.
- The component rows and the callback lists are iterated over snapshots, and all
  state settles before any callback runs, so handlers observe a consistent set even
  when someone joins and someone else leaves on the same tick.

definePlayerHelper is now memoized per engine. It was being called twice with the
global engine — once here, once inside addSyncTransport — so two systems were
scanning the same component every frame; now there is one.

Snapshot goldens regenerated: the rewrite moves SCENE_COMPILED_JS_SIZE_PROD by
roughly +2.6KB on every scene bundle, since observables.ts pulls this module into
all of them.

Author: LautaroPetaccio

packages/@dcl/sdk/src/network/message-bus-sync.ts

@@ -39,7 +39,7 @@ export function addSyncTransport(
 ) {
   // Profile Info
   const myProfile: IProfile = {} as IProfile
-  fetchProfile(myProfile!, getUserData)
+  const profileReady = fetchProfile(myProfile!, getUserData)
 
   const isServerAtom = Atom<boolean>()
   const isRoomReadyAtom = Atom<boolean>(false)
@@ -183,12 +183,29 @@ export function addSyncTransport(
     }
   })
 
-  players.onEnterScene((player) => {
-    DEBUG_NETWORK_MESSAGES() && console.log('[onEnterScene]', player.userId)
-    if (!isServerAtom.getOrNull() && myProfile.userId === player.userId) {
-      requestState()
-    }
-  })
+  // Deferred until the local identity is known: this compares against `myProfile.userId`,
+  // which `fetchProfile` populates asynchronously, so subscribing at module load would miss
+  // the local player's arrival whenever the profile lost that race.
+  //
+  // `requireProfile: false` — bootstrapping state needs the local identity, not the avatar
+  // profile, which can replicate seconds later or never.
+  // `replayPresent: true` — the players helper is shared per engine and this subscription is
+  // late by construction, so the local player has usually arrived already. Without the replay
+  // the bootstrap would never fire. `requestState` is guarded by `requestingState`, so an
+  // extra call is a no-op.
+  void profileReady
+    .catch(() => undefined)
+    .then(() => {
+      players.onEnterScene(
+        (player) => {
+          DEBUG_NETWORK_MESSAGES() && console.log('[onEnterScene]', player.userId)
+          if (!isServerAtom.getOrNull() && myProfile.userId?.toLowerCase() === player.userId.toLowerCase()) {
+            requestState()
+          }
+        },
+        { requireProfile: false, replayPresent: true }
+      )
+    })
 
   // Asks for the REQ_CRDT_STATE when its connected to comms
   RealmInfo.onChange(engine.RootEntity, (value) => {

packages/@dcl/sdk/src/network/utils.ts

@@ -8,8 +8,8 @@ import { IProfile } from './message-bus-sync'
 export function fetchProfile(
   myProfile: IProfile,
   getUserData: (value: GetUserDataRequest) => Promise<GetUserDataResponse>
-) {
-  void getUserData({}).then(({ data }) => {
+): Promise<void> {
+  return getUserData({}).then(({ data }) => {
     if (data?.userId) {
       const userId = data.userId
       const networkId = componentNumberFromName(data.userId)