PR-6 Phase 0: add Streamlit parity inventory

[utkuvibing]

Summary

• Add the read-only PR-6 Phase 0 Streamlit-to-Dash parity/deprecation inventory.
• Cover runtime entrypoints, all Streamlit pages, capability-level parity, shell/components, shared modules, packaging, tests, references, and reproducible evidence.
• Preserve the no-removal boundary: no runtime, dependency, packaging, README, or test changes.

Validation

• 86 targeted tests passed.
• Ruff passed.
• Broad-scan, route, component, test-node, table, and evidence audits passed.
• Existing host-only pip check mismatch is documented in the inventory.