v0.2.3: content[] value parity, corrected tool descriptions

content[] value parity, corrected tool descriptions

• content[] now renders every false, empty, and independently-sparse value structuredContent already carried — cancellation status, empty route lists, one-sided coordinates, and more (#23)
• wsdot_get_border_waits, wsdot_get_toll_rates, and wsdot_get_ferry_schedule descriptions corrected to match the live feeds (#33)
• docs/design.md reconciled against the shipped schemas, the security suite's injection assertions can now fail, and tests/ is typechecked by the same gate as src/ (#36, #37, #38)

CHANGELOG v0.2.3