Modularize remaining large smoke runners

[yvette-carlisle]

Summary

• Split Graphiti/Zep temporal smoke into graphiti_temporal_smoke modules with a thin legacy entrypoint.
• Split Letta core/archive smoke into letta_core_archive_smoke modules with a thin legacy entrypoint.
• Split RAGFlow Docker evidence smoke into sourced ragflow_smoke shell modules while preserving the existing command path.

Scale

• scripts/graphiti-zep-docker-temporal-smoke.py: 1305 -> 10 lines.
• scripts/letta-core-archive-export-readback-smoke.py: 1062 -> 10 lines.
• scripts/ragflow-docker-evidence-smoke.sh: 1278 -> 210 lines.
• New modules are scoped by context, models/common helpers, runtime, fixtures/artifacts, scoring, and runner flow; max new module size is 280 lines.

Validation

• python3 -m py_compile scripts/graphiti-zep-docker-temporal-smoke.py scripts/graphiti_temporal_smoke/.py scripts/letta-core-archive-export-readback-smoke.py scripts/letta_core_archive_smoke/.py
• bash -n scripts/ragflow-docker-evidence-smoke.sh scripts/ragflow_smoke/*.sh
• Default no-live Graphiti/Zep smoke with temp report/work dirs and artifact assertions.
• Default no-live Letta core/archive smoke with temp report/work dirs and artifact assertions.
• Default no-start RAGFlow smoke with temp artifact dir and artifact assertions.
• RUSTC=/run/current-system/sw/bin/rustc cargo make fmt-rust
• RUSTC=/run/current-system/sw/bin/rustc cargo make check: 403 passed, 92 skipped