fix(gateway): recover bounded pacing debt

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

@@ -7,6 +7,8 @@ Within each complete frame the source fixture SHALL reproduce pinned Apollo's so
 
 Native Apollo video ingress SHALL request a 2,195,456-byte socket receive buffer before media ping or worker startup and SHALL drain the connected video socket into a fixed FIFO pool of exactly 2,048 slots before the existing single decrypt/FEC processor. Each slot and the saturation scratch buffer SHALL be `apolloMediaMaximumPacket + 1` bytes so oversized datagrams remain rejected. A full pool SHALL NOT stop socket draining: each successfully read accepted-size discard SHALL increment both media-ingress and media-drop telemetry without allocation, while oversized reads SHALL retain the existing rejection accounting. Socket closure SHALL cancel the video read, and video/audio channels SHALL close only after the audio reader, video drain, and video processor exit. Audio and control ingress SHALL remain unchanged.
 
+The production fair pacer SHALL retain its 5 ms instantaneous catch-up ceiling. When a flow resumes later than that ceiling, it SHALL carry the remaining valid schedule debt only within the existing 250 ms provider-queue horizon and SHALL repay that debt using an interval no shorter than 20/21 of its nominal equal-tier fair-share interval. It SHALL return to the nominal interval when the debt is repaid. Simultaneous debt across eight equal-tier flows and the existing 25% and 50% capacity changes SHALL preserve the existing share-error contract and SHALL NOT exceed 105% of configured aggregate capacity in any rolling five-second window.
+
 #### Scenario: Healthy fixed profile
 - **WHEN** a frozen candidate runs one fixed profile for the normative duration in the isolated qualification command
 - **THEN** the harness emits compressed raw frame/path and gateway-process resource samples plus a summary tied to the exact command, CPU scope, timing-overhead method, topology, source commit, immutable Protocol version, environment, and payload hash
@@ -26,3 +28,7 @@ Native Apollo video ingress SHALL request a 2,195,456-byte socket receive buffer
 #### Scenario: Video ingress pool saturates
 - **WHEN** all 2,048 fixed video slots are occupied
 - **THEN** accepted-size datagrams are deliberately discarded through the fixed scratch buffer and counted as ingress plus drops, oversized datagrams remain rejected, and cancellation closes every media worker without a race or leak
+
+#### Scenario: Repeated media-loop host stalls
+- **WHEN** three approximately 95 ms scheduling debts are introduced at separated completed-public-frame barriers while source recovery continues
+- **THEN** the pacer limits instantaneous catch-up to 5 ms, repays each remaining debt at no more than 5% above nominal fair share, preserves every frame in exact order and bytes without provider or gateway drops, stays within the existing queue bounds, and closes cleanly on cancellation