Pyodide bridge should allow retry after init or package load failures

[bbopen]

Summary

PyodideBridge caches initPromise; if initialization or loadPackage fails once, subsequent calls keep failing without a retry path.

Failure mode

• Network error or missing package during init permanently bricks the bridge instance.

Repro (adversarial)

• Configure PyodideBridge with a bad indexURL or missing package.
• Call init() and verify failure.
• Fix config and call init() again; it should succeed after retry.

Acceptance criteria

• Failed init clears initPromise so the bridge can retry.
• Errors surface with actionable messages (missing package vs network).
• Tests cover retry behavior after a failing init.

[bbopen]

Resolved by PR #150. BoundedContext allows retry after init failures by resetting to 'idle' state.