fix(gateway): preserve qualification wire pacing

openspec/changes/truthful-fixed-frame-qualification/design.md

@@ -4,6 +4,8 @@ The current harness sends one fixed 1,179-byte payload per logical sample. It re
 
 The complete-frame fixture also must preserve the pinned Apollo source schedule. For each frame it derives packets per millisecond from the raw UDP block size at 80% of 1 Gbps, limits source batches to both 64 KiB and 64 packets, and carries the next-send time into the following frame. Waiting is context-cancellable. This is qualification-fixture behavior only; production transport and queue behavior remain unchanged.
 
+Because the bounded fixture uses loopback rather than a physical 1 Gbps link, each batch begins at its cumulative wire-rate offset. This preserves Apollo's raw-block rate and batch ceilings without collapsing multiple batches into an instantaneous loopback burst.
+
 ## Goals / Non-Goals
 
 **Goals:**

openspec/changes/truthful-fixed-frame-qualification/specs/gateway-qualification/spec.md

@@ -14,5 +14,5 @@ Within each complete frame the source fixture SHALL reproduce pinned Apollo's so
 - **THEN** the qualification command exits unsuccessfully without recording a passing candidate
 
 #### Scenario: Source-shaped Apollo pacing is preserved
-- **WHEN** the fixture emits 1,072-byte encrypted video shards for consecutive complete frames
-- **THEN** it uses 93 packets per millisecond, batches at most 61 shards, carries the integer next-send offset into the following frame, and emits no shard after a cancelled pacing wait
+- **WHEN** the fixture emits 1,072-byte encrypted video shards with 1,040-byte raw blocks for consecutive complete frames
+- **THEN** it uses 96 packets per millisecond, batches at most 63 shards at offsets derived from cumulative packet count, carries the next-send offset into the following frame, and emits no shard after a cancelled pacing wait