agent-platform release v4.108.2

The Substrate snapshot store expires nothing (giantswarm/agent-platform#792). The connectivity chart gave the CAPA bucket a 30-day Expiration rule and the CAPZ container a 30-day ManagementPolicy, on the premise that an actor whose snapshot expired boots cold from the golden image. Neither Substrate nor kagent does that, and Substrate already deletes every snapshot it replaces and an actor’s prefix with the actor, so the rule only ever deleted live data: the golden snapshot of a template whose revision had not changed in 30 days (its new actors then fail to start) and the only snapshot of an actor suspended that long (it cannot resume). The bucket now only aborts incomplete multipart uploads after a day, the container has no lifecycle policy, and kagent.harness.snapshotStore.crossplane.{aws,capz}.lifecycleDays are gone (a left-over key fails the render, naming it). The README documents the store’s retention and capacity. make verify-substrate-store asserts both providers’ rules and the guard; the kagent-pg backup bucket keeps its expiry.