feat(chat): migrate chat protocols onto pipelines

.agents/skills/audit-copilot-workarounds/SKILL.md

@@ -16,23 +16,24 @@ Copilot upstream.
 The provider code and the reference URLs beside each workaround are the
 inventory; there is no separate documentation list to reconcile.
 
-1. Start from
-   `packages/provider-copilot/src/interceptors/{openai-chat-completions,anthropic-messages,openai-responses}/index.ts`
-   and `packages/provider-copilot/src/defaults.ts`. Follow every registered
-   interceptor and default-enabled shim to its implementation and tests.
+1. Start from `packages/provider-copilot/src/pipelines.ts`,
+   `chat-pipelines.ts`, and `defaults.ts`. Follow every registered stage and
+   default-enabled shim to its implementation under `src/stages/` and its
+   mirrored tests under `__tests__/stages/`.
 2. Sweep the rest of `packages/provider-copilot/src` for non-pricing reference
    URLs and for vendor constants, thresholds, timeouts, retries, and pinned wire
    values that require a reference but may be missing one. Pricing citations
    belong to `fetching-models-pricing`; everything else remains in this audit.
-3. Include provider-level request/result shaping and catalog shaping even when
-   they are not interceptors. In particular, inspect `provider.ts`,
+3. Include request/result shaping and catalog shaping. Inspect `provider.ts`,
    `fetch-models.ts`, `known-models.ts`, `model-selection.ts`, and
-   `merge-claude-variants.ts` together with their imports and tests.
-4. Include the authentication fingerprint and management/data-plane behavior in
-   `auth.ts`, plus OpenAI Responses item identity and replay handling rooted at
-   `interceptors/openai-responses/item-id-membrane.ts`. Follow adjacent carrier and
-   compaction modules rather than assuming the interceptor registry contains the
-   whole workaround.
+   `merge-claude-variants.ts` together with their imports and tests. Exercise
+   data-plane behavior through the provider's operation pipelines rather than
+   its catalog-only instance.
+4. Include the authentication fingerprint and control/data-plane behavior in
+   `auth.ts` and `control-http.ts`, plus OpenAI Responses item identity and replay
+   handling rooted at `stages/openai-responses/item-id-membrane.ts` and
+   `opaque-item-id.ts`. Follow adjacent carrier and compaction modules; the
+   operation assemblies are entrypoints, not a complete workaround inventory.
 5. Record each item's owning module, reference URLs, affected source and target
    APIs, models, account scope, default flag state, tests, and exit condition:
    delete an obsolete workaround, refresh pinned mimicry, or retain it with

AGENTS.md

@@ -62,7 +62,6 @@
 | Package | `packages/dump` | Records pipeline runs and publishes diagnostics. |
 | Package | `packages/gateway` | Composes gateway services. |
 | Package | `packages/http` | Provides HTTP transport primitives. |
-| Package | `packages/interceptor` | Intercepts gateway traffic. |
 | Package | `packages/pipeline` | Runs stages over a fact record. |
 | Package | `packages/platform` | Defines portable runtime contracts. |
 | Package | `packages/protocols` | Defines protocol contracts. |

README.md

@@ -206,13 +206,13 @@ stage throws. Client JSON serialization runs inside settlement and publishes UTF
 while retaining the canonical content for inspection. Streaming quantities settle at the deferred exit. Explicit protocol and
 transport errors take precedence over the settlement's generic failure marker.
 
-Pipeline owns the stage-event format and object-space encoding. `@floway-dev/dump` owns
-run recording, stream references, completed NDJSON artifacts and metadata publication.
-Gateway supplies storage/broker ports and applies request admission, model attribution,
-HTTP byte measurement and retention policy. Closing waits for owned readers and deferred
-outcomes before storing the completed record and publishing its metadata. LogStream
-infrastructure is available on both platforms; live recording and its business readers
-remain outside these three PRs.
+`@floway-dev/dump` owns portable run recording, stream recording, metadata contracts,
+broker framing and wire conversion. Pipeline encodes stage facts, logs and protocol frames
+into one object space. Gateway owns attribution, admission, SQL storage and HTTP measurement.
+Closing waits for owned readers and deferred outcomes before storing the completed NDJSON
+record and publishing its metadata. The Collected view selects the recorded client stream and uses its
+`stream.end` event to establish recording completion. LogStream infrastructure is available
+on both platforms; live recording and its business readers remain outside these three PRs.
 
 Pipeline endpoints are assembled from individual stage modules. Each stage owns
 its request and response contract; a large stage keeps local helpers in the same