docs(performance): close modern runtime slice H

docs/ISSUES.md

@@ -362,7 +362,7 @@ retained typed snapshots instead of arrays. Evidence:
 
 ## #239 — Inbound net path allocates 3-4 arrays/objects per packet
 
-**Status:** OPEN
+**Status:** DONE — 2026-07-25, Modern Runtime Slice H-c
 **Severity:** LOW
 **Filed:** 2026-07-24
 **Component:** net
@@ -375,10 +375,15 @@ byte[], a second full copy into `Packet.BodyBytes`
 fragment count, which dominates during active play. The audit named only
 the outbound `ToArray()` copy.
 
-**Root cause / status:** 2026-07-24 audit review finding. In scope for plan
-Slice H-c (requires the §0.3 freeze authorization); invariants pinned in
-the plan amendment (single outstanding receive, arrival order,
-ack-per-packet).
+**Resolution:** One cancellable pooled receive owner now preserves kernel
+arrival order while packet headers, optionals, checksum verification, and
+single-fragment dispatch borrow the queued datagram. Only multi-fragment state
+whose lifetime crosses datagrams is copied. Warm production decode allocates
+zero bytes; the 500,000-packet differential benchmark improved throughput
+8.666x and removed approximately 400 bytes per packet. Direct recurring sends
+also frame into caller storage with zero warmed allocation. Connected
+login/portal/dungeon/reconnect and exact graceful disconnect pass. Evidence:
+`docs/research/2026-07-25-slice-h-closeout.md`.
 
 **Files:** `src/AcDream.Core.Net/NetClient.cs:63-78`;
 `src/AcDream.Core.Net/Packets/PacketCodec.cs:58,64`;