Add adapter session codecs with cwd-aware resume and unknown-session retry

Introduce AdapterSessionCodec interface for structured session serialization,
deserialization, and display ID extraction. Implement codecs for claude_local
and codex_local adapters with cwd validation — sessions saved for a different
working directory are not resumed. Both adapters now return sessionParams and
sessionDisplayId alongside legacy sessionId.

Add isCodexUnknownSessionError detection and automatic retry with fresh session
for codex_local (matching existing claude_local behavior). Inject approval
context env vars (PAPERCLIP_APPROVAL_ID, PAPERCLIP_APPROVAL_STATUS,
PAPERCLIP_LINKED_ISSUE_IDS) into adapter environments.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/__tests__/adapter-session-codecs.test.ts

@@ -0,0 +1,64 @@
+import { describe, expect, it } from "vitest";
+import { sessionCodec as claudeSessionCodec } from "@paperclip/adapter-claude-local/server";
+import { sessionCodec as codexSessionCodec, isCodexUnknownSessionError } from "@paperclip/adapter-codex-local/server";
+
+describe("adapter session codecs", () => {
+  it("normalizes claude session params with cwd", () => {
+    const parsed = claudeSessionCodec.deserialize({
+      session_id: "claude-session-1",
+      folder: "/tmp/workspace",
+    });
+    expect(parsed).toEqual({
+      sessionId: "claude-session-1",
+      cwd: "/tmp/workspace",
+    });
+
+    const serialized = claudeSessionCodec.serialize(parsed);
+    expect(serialized).toEqual({
+      sessionId: "claude-session-1",
+      cwd: "/tmp/workspace",
+    });
+    expect(claudeSessionCodec.getDisplayId?.(serialized ?? null)).toBe("claude-session-1");
+  });
+
+  it("normalizes codex session params with cwd", () => {
+    const parsed = codexSessionCodec.deserialize({
+      sessionId: "codex-session-1",
+      cwd: "/tmp/codex",
+    });
+    expect(parsed).toEqual({
+      sessionId: "codex-session-1",
+      cwd: "/tmp/codex",
+    });
+
+    const serialized = codexSessionCodec.serialize(parsed);
+    expect(serialized).toEqual({
+      sessionId: "codex-session-1",
+      cwd: "/tmp/codex",
+    });
+    expect(codexSessionCodec.getDisplayId?.(serialized ?? null)).toBe("codex-session-1");
+  });
+});
+
+describe("codex resume recovery detection", () => {
+  it("detects unknown session errors from codex output", () => {
+    expect(
+      isCodexUnknownSessionError(
+        '{"type":"error","message":"Unknown session id abc"}',
+        "",
+      ),
+    ).toBe(true);
+    expect(
+      isCodexUnknownSessionError(
+        "",
+        "thread 123 not found",
+      ),
+    ).toBe(true);
+    expect(
+      isCodexUnknownSessionError(
+        '{"type":"result","ok":true}',
+        "",
+      ),
+    ).toBe(false);
+  });
+});

server/src/adapters/index.ts

@@ -4,6 +4,7 @@ export type {
   AdapterExecutionContext,
   AdapterExecutionResult,
   AdapterInvocationMeta,
+  AdapterSessionCodec,
   UsageSummary,
   AdapterAgent,
   AdapterRuntime,

server/src/adapters/registry.ts

@@ -1,7 +1,7 @@
 import type { ServerAdapterModule } from "./types.js";
-import { execute as claudeExecute } from "@paperclip/adapter-claude-local/server";
+import { execute as claudeExecute, sessionCodec as claudeSessionCodec } from "@paperclip/adapter-claude-local/server";
 import { agentConfigurationDoc as claudeAgentConfigurationDoc, models as claudeModels } from "@paperclip/adapter-claude-local";
-import { execute as codexExecute } from "@paperclip/adapter-codex-local/server";
+import { execute as codexExecute, sessionCodec as codexSessionCodec } from "@paperclip/adapter-codex-local/server";
 import { agentConfigurationDoc as codexAgentConfigurationDoc, models as codexModels } from "@paperclip/adapter-codex-local";
 import { processAdapter } from "./process/index.js";
 import { httpAdapter } from "./http/index.js";
@@ -9,6 +9,7 @@ import { httpAdapter } from "./http/index.js";
 const claudeLocalAdapter: ServerAdapterModule = {
   type: "claude_local",
   execute: claudeExecute,
+  sessionCodec: claudeSessionCodec,
   models: claudeModels,
   supportsLocalAgentJwt: true,
   agentConfigurationDoc: claudeAgentConfigurationDoc,
@@ -17,6 +18,7 @@ const claudeLocalAdapter: ServerAdapterModule = {
 const codexLocalAdapter: ServerAdapterModule = {
   type: "codex_local",
   execute: codexExecute,
+  sessionCodec: codexSessionCodec,
   models: codexModels,
   supportsLocalAgentJwt: true,
   agentConfigurationDoc: codexAgentConfigurationDoc,

server/src/adapters/types.ts

@@ -8,5 +8,6 @@ export type {
   AdapterExecutionResult,
   AdapterInvocationMeta,
   AdapterExecutionContext,
+  AdapterSessionCodec,
   ServerAdapterModule,
 } from "@paperclip/adapter-utils";