docs(lite): document the four-stream setup minimum

drafts/draft-lcurley-moq-lite.md

@@ -226,6 +226,9 @@ See [Transports](#transports) for the bindings.
 
 How the underlying connection is authenticated is out-of-scope for this draft.
 
+A subscriber that holds an Auth Stream and an Announce Stream needs credit for at least 4 concurrent bidirectional streams to establish a subscription.
+AUTH and ANNOUNCE occupy two streams for the session lifetime, and TRACK is briefly held alongside SUBSCRIBE, requiring two more.
+
 ## Transports {#transports}
 moq-lite defines five transport bindings.
 All five carry the same control and data streams defined elsewhere in this document; they differ only in how QUIC streams are multiplexed onto the underlying connection.

quest/m1/stream-credit/README.md

@@ -42,7 +42,7 @@ receiving every group, and nothing hanging.
 
 ## Required
 
-- [A departed subscription releases its streams](/quest/m1/stream-credit/release-on-leave.md) - on lite-07 a subscription whose reader left frees its upstream streams, so 3 slots serve the next one
+- [An abandoned subscription setup releases its streams](/quest/m1/stream-credit/release-on-leave.md) - release TRACK and pending SUBSCRIBE when demand leaves during setup
 - [Open streams](/quest/m1/stream-credit/open-streams.md) - each session lists its open streams and, where the transport can tell, which are fully acknowledged
 - [Reset fallback](/quest/m1/stream-credit/reset-fallback.md) - a waiting higher-priority open resets the lowest-priority stream, one reset in flight per waiting open
 - [Takeover](/quest/m1/stream-credit/takeover.md) - on lite-07 a higher-priority group takes over an acknowledged stream, and a group that lost its stream resumes

quest/m1/stream-credit/release-on-leave.md

@@ -1,23 +1,28 @@
-# [S] A departed subscription releases its streams
+# [S] An abandoned subscription setup releases its streams
 
 ## Goal
 
-On lite-07, when a subscription's last reader leaves, every stream it held
-upstream is released, so the credit returns for the next subscription. A
-relay test with exactly 3 bidirectional stream slots serves a second
-subscription after the first leaves, as it already does on moq-transport-22
-and on lite-07 with 4 slots.
+On lite-07, a subscription whose last reader leaves while SUBSCRIBE is still
+opening or awaiting its answer releases its upstream TRACK and pending
+SUBSCRIBE, so their credit can serve later requests.
 
 ## Plan
 
-Found 2026-11-04 by the scheduler's relay test
-(`a_subscription_past_the_credit_is_served_once_credit_returns`, from
-[moq-dev/moq#7894](https://github.com/moq-dev/moq/pull/7894)): on lite-07 with exactly 3 bidirectional slots, a second
-subscription is never served after the first leaves, while 4 slots work and
-moq-transport-22 works with 3. The likely cause is a stream the departed
-subscription keeps open upstream (its request stream, or a companion such as
-the Tracks stream) after its reader leaves. Reproduce it with the 3-slot
-relay test first, find which stream stays open and on which side, fix it, and
-set that relay test's credits back to the tight case. With opens now waiting
-for credit instead of failing, a leaked stream stalls later subscriptions
-silently, and low-credit peers such as browsers hit it first.
+Decided 2026-11-05 (maintainer, /quest-plan): ✅ Keep the TRACK/SUBSCRIBE
+handshake and document the minimum of four concurrent bidirectional streams.
+AUTH and ANNOUNCE hold two slots for the session lifetime; TRACK is briefly
+held alongside SUBSCRIBE. Three slots cannot establish the first subscription.
+Rejected: metadata on SUBSCRIBE (overlaps other lite-07 work and saves no round
+trip), and releasing TRACK early during a live setup.
+
+The established-subscription regression
+`a_subscription_past_the_credit_is_served_once_credit_returns` already passes
+with four slots. Keep that budget. The three-slot reproduction did not show a
+departure leak.
+
+Local review identified remaining pending-setup cleanup: `ServeLoop::poll` in
+`ServeMode::Establish` waits on establishment without observing lost demand,
+while holding `HeldTrack`. Reproduce abandonment with at least four slots,
+keeping the publisher and route live, then ensure both the TRACK hold and the
+pending SUBSCRIBE registration are released when demand leaves. Preserve the
+hold while demand remains. Cover Rust and its JS counterpart where applicable.

rs/moq-net/tests/integration/stream_credit.rs

@@ -81,8 +81,8 @@ async fn one_stream_credit_serves_every_backlogged_group() {
 /// subscription past the publisher's credit is served once an earlier one leaves.
 #[kio::test]
 async fn a_subscription_past_the_credit_is_served_once_credit_returns() {
-	// Room for the bidirectional streams the session holds before the second subscription:
-	// the second then waits for one of the first's.
+	// lite-07 needs 4: session-long AUTH and ANNOUNCE plus TRACK held until SUBSCRIBE answers.
+	// Three is below the setup minimum; the second subscription waits for the first's credit.
 	for (version, credit) in [("moq-lite-07-wip", 4), ("moq-transport-22", 3)] {
 		let version: Version = version.parse().unwrap();
 		let publisher = origin(1);