[viralcodex]

Changes

• Model connection handshake, initial state publication, readiness, and closure explicitly.
• Reject stale readiness completions and prevent reconnection after disposal.
• Reconnect failed or ended session-event subscriptions with cancellable bounded backoff.
• Keep failed session cleanup owned and retryable without blocking other sessions.
• Split the old all-in-one main test, consolidate overlapping scenarios, and enforce production complexity below 10.
• Rebuild shipped bundles.

Verification

• Exact PR tree: release:check passes on Node 24.13.0, including installed-package loading.
• 296 tests pass, one existing Bun-only skip.
• Lifecycle suites pass three consecutive runs.
• One delayed local run hit a test timeout; the isolated test and complete release-check rerun passed without changing its timeout.

Sequence

3 of 3. Builds on merged #28 and #29. Release preparation follows after this PR passes CI and merges.

[viralcodex]

Reviewed handshake/publication failure, stale readiness completion, watcher termination/reconnection, retry ownership, disposal cancellation, and isolation between concurrent session cleanups. Exact-tree release checks pass locally and in Linux CI: https://github.com/viralcodex/opencode-demul/actions/runs/42032203229. All 296 tests pass with one existing skip; the four lifecycle suites also pass three repeated runs. Old overlapping tests were consolidated rather than simply accumulating new cases.