Request-scoped lifecycle and context propagation #362

Area: Application, DI\Container, HTTP, console

Problem

Doppar already drops resolved request-scoped services, but the lifecycle is not exposed as a first-class context that can carry request, job, CLI, and tenant metadata. This makes cleanup and correlation inconsistent across entry points.

Proposal

Introduce an immutable ExecutionContext and explicit lifecycle hooks for request, console, and future worker executions. Bindings may declare a scope (singleton, execution, or transient) and the active context is available through the container and a small facade.

Acceptance criteria

• Context creation, nesting, and teardown are covered by unit tests.
• Execution-scoped services cannot leak between two sequential requests.
• Context metadata is available to the logger without global mutable state.
• Existing singleton behavior remains backward compatible.