Ruleset: query and path parameters must be camelCase

[ExtraToast]

What to build

A rule requiring query and path parameters to be camelCase.

Only one service currently violates this, and its rename is a separate ticket — this rule locks the convention in once that lands, so the estate cannot drift back.

Acceptance criteria

• A snake_case parameter fails the check
• All three estate specs pass when the rule merges
• The rule is shown to fail against a deliberately bad fixture

Blocked by

• Add vacuum lint inputs and a ruleset requiring operationId
• Rename snake_case query parameters to camelCase (knowledge)