[WIP] feat: add optional 'ageTiers' for granular risk assessment

[yyeAduna]

Introduce an optional input parameter ageTiers (list of integers) that enables a "Tiered Response" mode, where the highest tier is the maxAge.

What type of PR is this?

enhancement/feature
What this PR does / why we need it:

Introduces an additive, optional mechanism to query device swap "recency tiers" without exposing exact timestamps.

Current consumers of the API (e.g., banks) often need more granular signals to assess account-takeover risk alongside their own data for their ML based risk engine. A simple boolean result (True/False) is form of lossy compression and doesn’t provide enough detail, while returning the underlying event date/time isn’t feasible due to strict privacy requirements (e.g., GDPR) and operator restrictions.

Also due to privacy and security reasons, a bank won't want to leak the value/risk of their customer's operation or disclose their internal risk policies to third party by using different maxAge for each individual transactions. The standard age-tier approach will help to protect bank customers' privacy and bank's corporate security.

Solution:

Adds ageTiers (Request): An optional list of integer buckets (e.g., [1, 4, 24]).

Adds tierIndex (Response): An optional integer indicating which bucket the swap falls into.

Which issue(s) this PR fixes:

Fixes #80

Special notes for reviewers:

Backward Compatibility Analysis: This change is strictly additive.

The maxAge parameter remains required and continues to drive the standard swapped boolean logic.

If ageTiers is omitted by the client (legacy behavior), the API behaves exactly as the current v1.0.0 spec, and tierIndex is not returned.

Privacy Impact: This improvement enhances privacy by allowing operators to share risk granularity without revealing the exact time of the swap (PII).Also allow the banks (Clients) take full advantage of the function without revealing the value/risk of customer's bank transactions/operations.

[bigludo7]

Thanks @yyeAduna

let discuss your proposal in next Number Insights meeting next week!

cc: @fernandopradocabrillo @AxelNennker