feat: raise the minimum supported version to 1.32

[bryantbiggs]

Raises the minimum supported cluster version from 1.30 to 1.32, so eksup only accepts versions EKS still supports. EKS extended support ended for 1.30 on 2026-07-23 and ends for 1.31 on 2026-11-26. 1.32 is supported until 2027-03-23.

• MINIMUM goes from 30 to 32.
• data.yaml drops the 1.30, 1.31 and 1.32 entries. The earliest possible upgrade target is now 1.33, so nothing could read them.
• A new unit test checks that data.yaml has release data for every target from MINIMUM + 1 to LATEST, so a version bump that forgets the data file fails in CI rather than at runtime.
• The test fixtures move from a 1.30 cluster to 1.32. Node versions and targets move up by two to keep every version gap the same. The snapshot changes are version strings and release links only.
• The e2e test for a deprecation link being present is removed. Its only data was the 1.32 entry, and no supported target has a deprecation-guide section now. The link rendering itself is unchanged and is used again when a future release removes APIs.

No check is newly retired. Only K8S009 and K8S010 end before 1.32, and they were already retired.

Local gate: nightly fmt, clippy -D warnings, cargo test --all and xtask generate-all --check pass.

[bryantbiggs]

Folded into #199.