Imagegen Bridge 0.3.0

Version 0.3.0 makes capacity policy fully operator-controlled and makes every failure more useful to people and clients.

• Bridge concurrency, queue capacity, and listener connections now accept a positive integer or "unlimited"; the default profile adds no artificial bridge-side concurrency cap.
• Multi-image requests accept up to 255 outputs and use max_parallel_outputs = "auto" by default. Five requested images therefore start five independent provider calls instead of waiting in bridge-created waves.
• Every stable error includes redaction-safe recovery suggestions. CLI human output displays them, JSON preserves them, and both typed SDKs expose them.
• Update notices now show installed/latest versions and the exact dry-run command appropriate for standalone or container installations. Passive checks remain cached, non-blocking, terminal-only, and telemetry-free.
• Configuration schemas, OpenAPI, dashboard copy, Python and TypeScript types, examples, capacity guidance, and troubleshooting documentation were updated.
• Deterministic tests cover five concurrent provider calls, unlimited admission, named environment/CLI overrides, updater guidance, and SDK error propagation.

Payload, image-decoding, deadline, circuit-breaker, and artifact safety boundaries remain intact. Operators can still choose finite concurrency and queue values when they want backpressure or need to accommodate upstream rate limits.