Track RDS and Aurora engine support lifecycle dates

What

Replace static RDS engine-version checks with maintained lifecycle data, including Aurora standard-support and Extended Support dates.

Why

Hard-coded version lists become stale and cannot distinguish a version that is unsupported from one that is entering paid Extended Support. Date-aware evidence gives teams time to plan upgrades and identifies avoidable support charges.

Details

• Establish an authoritative, updateable source for engine lifecycle dates and document its refresh process.
• Cover supported RDS engines and Aurora MySQL and PostgreSQL versions where AWS publishes standard-support and Extended Support dates.
• Produce separate findings for approaching paid support, currently billed Extended Support, and unsupported versions.
• Include engine, version, relevant lifecycle date, days remaining, and support state as evidence.
• Keep static IaC and live discovery evaluation on the same generated lifecycle catalog.

Related: #112

Start by locating the existing static RDS engine-version checks and reviewing related issue #112 as entry points for the lifecycle catalog design. Done means an authoritative, refreshable catalog covers supported RDS and Aurora versions, produces distinct support-state findings with dates and days remaining, and is shared by static IaC and live discovery evaluation.