sync wire fix (bare array + string delivery_id), WS delivery acks, dedup, terminal closes — 1.0.31

[sanctrl]

What

Python mirror of agentchat-typescript#1. The /v1/messages/sync drain read batch.get('envelopes') off what production actually sends (a bare JSON array) and gated delivery ids on isinstance(int) against string del_ cursors — every offline drain silently returned zero rows and never acked. The 1.0.3 release was the directory-auth change only; this path was never fixed until now.

Changes

• sync() → list[SyncRow] (TypedDict, unknown fields pass through); sync_ack(str) → {'acked': int}; last_sync_delivery_id() helper
• Drain rebuilt: cursor pagination, positional ack of the settled prefix, clean-prefix stop on invalid rows, no-progress guard, errors via on_error — the silent failure mode is structurally impossible now
• Capability-negotiated WS acks per server docs/realtime-delivery-ack.md: dormant unless hello.ok echoes the capability; ack only after handlers settle; exception ⇒ no ack ⇒ redelivery
• Bounded message-id dedup (default 2048) across live+drain
• Close codes 1008/4401/4403 terminal (client's own HELLO-timeout 1008 self-close exempt, test-locked)
• Paginator audit vs live routes: contacts/agents keys match — no drift; nothing reads items
• New wire-contract suite incl. a true end-to-end drain over a respx-mocked wire asserting the exact ack body

Verification

• ruff clean, mypy strict clean, pytest: 136 passed / 1 skipped (live-gated) — the exact CI gate trio
• Version 1.0.31 (pyproject + _version.py, consistency now test-enforced)

Release

Not published. Follow-up after release: raise agentchat-hermes' SDK floor so the plugin picks up the fixed drain.