Fix session list cwd pagination

[OldKrab]

Summary

• forward ACP's session/list cwd filter to Codex App Server's thread/list
• apply the filter before App Server pagination and cursor generation
• match Codex CLI ordering with sortKey: "updated_at" and sortDirection: "desc"
• leave limit unset so App Server keeps its default page size
• cover both legacy string-only and newer string-or-array cwd handling
• keep the local path normalization of the returned page (Windows paths, basename filters)

Root cause

CodexAcpClient.listSessions requests a global App Server page, then filters that page locally by cwd. A requested workspace can therefore receive an empty page with a nextCursor belonging to unrelated global results even when matching sessions exist on later pages.

Passing the scalar ACP cwd through to thread/list is compatible with both App Server forms and makes the returned page and cursor belong to the filtered result set.

The request also uses the same updated-at descending ordering as Codex CLI. The CWD, opaque cursor, and ordering parameters are forwarded on every page without specifying a page-size limit.

Relation to the sessionIndex extension

#590 already filters by cwd in App Server for clients that declare sessionIndex. This change applies the same filtering to the plain session/list path used by every other client. It therefore changes the request pinned by session-index-list-params-legacy.json; the snapshot is updated to include cwd, sortKey, and sortDirection.

Verification

• npx vitest run src/__tests__/CodexACPAgent/list-sessions.test.ts src/__tests__/CodexACPAgent/session-index.test.ts
• npm run typecheck
• npm test (1500 passed, 36 skipped)