Remove BDD process-global state (#492) - #580

Summary

• Remove process-global environment and working-directory coordination from rstest-bdd scenarios.
• Run netsuke scenarios in isolated child processes.
• Use injected environment boundaries for in-process configuration, manifest, IR, and standard-library scenarios.
• Remove EnvLock handling and global-state cleanup from TestWorld.
• Preserve explicit relative configuration selector semantics under -C.
• Add fixed and property-based coverage for relative and absolute --config and NETSUKE_CONFIG paths.
• Preserve non-UTF-8 -C and --directory values during BDD CLI parsing.
• Update BDD fixtures, steps, feature files, the developer guide, and ADR-008 to document Route A and Route B boundaries.
• Address issue #492 by removing BDD scenario serialization through process-global state.

Walkthrough

Update configuration discovery tests to preserve process CWD semantics. Remove process-global CWD coordination from BDD fixtures and steps. Add explicit CLI token handling and document the supported BDD isolation routes.

Changes

Configuration discovery and BDD state handling

Suggested labels: Issue

Poem

Relative paths keep their place,
BDD steps leave no global trace.
Tokens carry directories,
Guards serve direct CWD testaries.
Clear routes guide each test run.

Merge Risk: 🔵 Low · up to baa08

The change removes process-global BDD environment and working-directory mutation while preserving explicit path behavior. Merge is reasonable with owner follow-up for bounded test portability and reliability issues, including a negative discovery test that can be influenced by an unrelated process-CWD file.

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Reviewer's Guide

Removes the remaining process-global environment and CWD guarding from BDD test infrastructure by relying on explicit paths and the CLI -C/--directory contract, while adding a regression test to lock in the new discovery behavior for relative config paths.

Flow diagram for explicit configuration discovery with -C

flowchart TD
    A[CLI with directory and config path] --> B{path.is_relative}
    B -->|yes and directory set| C[directory.join path]
    B -->|no or directory unset| D[path.to_path_buf]
    C --> E[load_layers_from_path_with_warning]
    D --> E
    E --> F[Explicit FileLayerTrace with effective path]

File-Level Changes

Assessment against linked issues

Possibly linked issues

• Migrate rstest-bdd scenarios off in-process environment and CWD mutation #492: The PR directly implements the issue’s required environment/CWD migration and removes the global state guards.
• Migrate rstest-bdd scenarios off in-process environment and CWD mutation #492: The PR directly implements issue Migrate rstest-bdd scenarios off in-process environment and CWD mutation #492 by removing BDD global-state guards and replacing CWD-dependent behavior with explicit paths.

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