What this does

Adds createOutboundSync, an application-facing controller that publishes exact committed local operations through one SyncPeer and one or more outbound transports.

Applications report a local edit once with queueOps(...). The controller deduplicates pending operations by operation ID, wakes low-level live subscriptions, and keeps exact uploads queued until a target is available and online.

Correctness guarantees

• A timeout aborts the underlying SyncPeer.pushOps; signing or later chunks cannot continue after the controller retries.
• Replacing or removing targets aborts the active snapshot and replays its operations against the current target set.
• Concurrent flush() callers share one drain barrier, including work queued during the active run.
• Repeated attachment of the same target shares one peer attachment with reference-counted, idempotent cleanup.
• Failed pushes restore the exact batch ahead of newly queued work without creating an unconditional retry loop.
• Observer exceptions cannot corrupt queue state or create unhandled rejections.
• close() aborts active work, clears the queue, and prevents late restoration.

Clean integration with #191

This PR is stacked on #191 and preserves its per-exchange Hello correlation, transport-owned state, and exact capability leases. It does not restore the removed global waitForAck/Hello-waiter path or add a compatibility adapter.

Fast paths and limits

• Empty batches are ignored and duplicate operations coalesce by meta.id.
• Offline or targetless flushes retain work without network activity or error callbacks.
• Calls without a timeout or abort signal register no controller cancellation timer.
• Cancellation cannot retract a frame whose send() already began; later frames and session continuation are stopped, and operation IDs make a late valid frame idempotent.

Size

The cohesive layer is 8 files, +984/-38. Playground adoption, discovery, UI, lockfile churn, and unrelated op-ref behavior remain outside this PR.

Validation

• sync protocol: 58/58
• @treecrdt/sync: 32/32
• outbound controller: 12/12 focused tests
• TypeScript builds pass