feat: per-model throughput (tok/s) tracking + metrics endpoint

New throughput-store extension records one token-weighted sample per turn
(model, output tokens, pure generation time = Σ step genTotalMs) into a
day-bucketed KV store, and aggregates per-model tok/s = Σtokens / Σgen-seconds
over a day/week/month (server-local boundaries; week = ISO Mon–Sun).

transport-http records a sample per turn (logged) and serves
GET /metrics/throughput?period=day|week|month&date=<...>. The response is typed
as transport-contract's ThroughputResponse, so store/wire drift is a compile
error. Pure period + aggregate logic fully unit-tested.

1 files changed, 2 insertions, 0 deletions

diff --git a/packages/host-bin/src/main.ts b/packages/host-bin/src/main.ts
index ec51d11..7f219d1 100644
--- a/packages/host-bin/src/main.ts
+++ b/packages/host-bin/src/main.ts
@@ -23,6 +23,7 @@ import { extension as sessionOrchestratorExt } from "@dispatch/session-orchestra
 import { createSqliteStorage, extension as storageSqliteExt } from "@dispatch/storage-sqlite";
 import { createLoadedExtensionsExtension } from "@dispatch/surface-loaded-extensions";
 import { createSurfaceRegistryExtension } from "@dispatch/surface-registry";
+import { extension as throughputStoreExt } from "@dispatch/throughput-store";
 import { extension as toolReadFileExt } from "@dispatch/tool-read-file";
 import { createTransportHttpExtension } from "@dispatch/transport-http";
 import { createTransportWsExtension } from "@dispatch/transport-ws";
@@ -62,6 +63,7 @@ const CORE_EXTENSIONS: readonly Extension[] = [
 	authApikeyExt,
 	providerOpenaiCompatExt,
 	toolReadFileExt,
+	throughputStoreExt,
 	sessionOrchestratorExt,
 	createTransportHttpExtension(),
 	// Surface extensions — dependency order: surface-registry first, then consumers.