client.ts disables max-lines and keeps handshake, submit, resume, heartbeat, and subscriptions together

[nficano]

Summary

Second-pass well-written-code audit finding. packages/client/src/client.ts has a file-level max-lines disable and still centralizes the full client lifecycle in an 861-line file.

Evidence

• packages/client/src/client.ts:1 disables max-lines for the whole file.
• packages/client/src/client.ts:63 through packages/client/src/client.ts:70 list the surface handled here: handshake, submit, cancel, close, ack, listJobs, and subscribe.
• The file currently has 861 lines.

Why it matters

The client is a concurrency-heavy protocol boundary. Keeping connection state, pending accepts, resume, heartbeat/liveness, job submission, list-jobs, subscriptions, and close semantics in one suppressed file makes review difficult and lets new behavior accumulate without an architectural boundary.

Proposed fix

Split the implementation into cohesive modules, for example connection/session lifecycle, job submission/handles, subscription/list-jobs operations, and heartbeat/liveness. Keep ARCPClient as the public facade and remove the file-level max-lines disable.

Acceptance criteria

• packages/client/src/client.ts no longer needs a file-level max-lines disable.
• Extracted modules preserve the existing public API and tests.
• New or moved tests cover the extracted lifecycle/submission/subscription boundaries.