feat: verify portable decision price-series artifacts

[Pigbibi]

What

Add a portable daily decision-data projection contract and a byte-only verifier for the private runtime artifact adapter.

Verification boundary

The verifier requires a canonical research input manifest whose digest matches the public DecisionDataBinding, checks the decision-price-series member hash, and then matches strategy scope, session date, adjustment basis, and source identities before returning PriceSeries values.

Safety

• No storage URI, credential, account identifier, or execution quote enters the public binding or execution report.
• The module is transport-neutral; deployment-specific storage access remains an injected adapter.
• P1 native validators stay authoritative for provider-specific source assurance. This is their portable runtime projection, not a replacement for P1 or promotion gates.

Verification

• 152 focused contract tests passed.
• Ruff passed for the new module and tests.