OpenClaw Signals: Execution Isolation, Retry Backoff, and the Manifest Validation Shift

PR #329: Execution Isolation for Plugin Sandbox

This PR introduces stricter process-level isolation for plugin execution, preventing one plugin crash from taking down the host or other plugins. For builders, this is a foundational reliability upgrade that makes sandboxed environments genuinely fault-tolerant.

Issue #1560: Implement Exponential Backoff for Retry Logic

The community is pushing for smarter retry logic with exponential backoff instead of fixed delays. This matters for reducing thundering herd problems and making flaky task execution more resilient under load.

PR #328: Manifest Validation Bypass Option

This adds an opt-in flag to bypass manifest validation during rapid iteration cycles. Useful for developers prototyping new plugins, but it introduces a clear trade-off between speed and safety.

PR #327: Unified Hook Error Handling

Standardizes error propagation across all hook types, making debugging plugin interactions much more predictable. Reduces the cognitive overhead of tracing failures through the execution pipeline.