fix(realtime): survive signal outages and per-server identities

Peer recovery burned its whole retry budget while signaling was down, then
dropped the tracker with no re-arm, so a peer stayed dead until an unrelated
roster event healed it. Recovery now waits for a usable transport before
spending an attempt.

Initiator election also compared a home actor id against foreign roster ids,
which is not antisymmetric across signal servers - both sides offered, or
neither did. Election moves into `peer-role.rules` and compares ids only
within one signal server's identity space.

toju-app/src/app/infrastructure/realtime/peer-role.rules.ts

@@ -0,0 +1,37 @@
+/**
+ * Deterministic WebRTC role election.
+ *
+ * Both ids must come from the **same signal server's identity space**. One human has a
+ * separate account - and therefore a separate actor id - on every signal server they are
+ * provisioned on, so comparing a home id against a foreign actor id is not antisymmetric:
+ * each side compares its own home id against the other's foreign id, and both can elect
+ * themselves initiator (glare) or neither can (no offer ever sent).
+ */
+export function shouldInitiatePeerConnection(
+  localActorId: string | null | undefined,
+  remoteActorId: string | null | undefined
+): boolean {
+  const local = localActorId?.trim();
+  const remote = remoteActorId?.trim();
+
+  if (!local || !remote)
+    return false;
+
+  if (local === remote)
+    return false;
+
+  return local < remote;
+}
+
+/**
+ * Perfect-negotiation politeness, derived from the same election so the two can never
+ * disagree: the elected initiator is the impolite side and keeps its offer, the other
+ * side rolls back. Falls back to polite when the local actor id is unknown, so an
+ * unidentified client yields instead of deadlocking the negotiation.
+ */
+export function isPoliteOnOfferCollision(
+  localActorId: string | null | undefined,
+  remoteActorId: string | null | undefined
+): boolean {
+  return !shouldInitiatePeerConnection(localActorId, remoteActorId);
+}