Stream runtime trace events and package 0.3.2

[RockingSisyphus]

Summary

• Stream runtime trace events directly to runtime_trace.jsonl and stop retaining full runtime.events in memory or hook payloads.
• Keep trace summaries in RunResult.runtime.* via event_count, trace_path, and events_streamed.
• Update nested loop/nodeset trace propagation, output summary handling for large prediction mappings, docs, tests, and sandbox hook examples.
• Add the vibeflow_distribution-0.3.2.zip release package.

Validation

• PYTHONPATH=src python -m compileall -q src/vibeflow tests/unit
• PYTHONPATH=src pytest -q tests/unit/test/strict_runtime.py tests/unit/test/strict_core.py tests/unit/test/strict_plugins.py tests/unit/test/strict_base_config_examples.py
• PYTHONPATH=src pytest -q tests/unit
• PYTHONPATH=src python examples/integration_sandbox/run_all.py
• python vibeflow_distribution/run.py verify-kernel
• unzip -t vibeflow_distribution-0.3.2.zip