v0.3.0

This alpha release adds immediate push-based cold activation, a current NVIDIA A10 profile, and
expanded real-accelerator evidence for Hearth alongside Volcano and Kthena. The API remains
v1alpha1, and Hearth is not production-ready for shared or customer-facing workloads.

Added

• An opt-in, co-located KEDA ExternalScaler that streams cold activation immediately while retaining
  queue metrics for scale-out, scale-down, observability, and rollback.
• An activation lease for reject-mode cold starts, including current-state replay across scaler
  reconnects and a no-GPU E2E mode for the external-push path.
• An NVIDIA A10 profile and reproducible K3s validation report for vLLM v0.25.1.
• A hardware-neutral, command-driven Hearth and Kthena demo showing a hot model alongside a
  long-tail model that activates from zero and returns to zero.

Changed

• Helm and the manager accept gateway.scalerMode / --scaler-mode; metrics-api remains the
  compatibility default and external-push requires one gateway replica.
• The A100 example now uses device-specific names, vLLM v0.25.1, the positional model argument,
  and a conservative one-replica default. Its historical hardware evidence remains tied to vLLM
  v0.22.0 pending focused revalidation of the new stack.
• The primary quickstart now uses the physically validated A10 profile.

Removed

• The redundant standalone A100 HostPath manifest. cache.strategy: HostPath remains available in
  the API; bundled profiles consistently use NodeLocalPVC and require a dynamic StorageClass.

Fixed

• Use vLLM's current vllm:kv_cache_usage_perc metric in all runtime profiles, the CPU stub, and
  the optional Grafana dashboard.
• Correct the recorded Ascend 910B3 identity and tighten the evidence boundaries in the 910B3 and
  310P validation reports.
• Keep prerelease image publication from moving the stable latest operator and gateway tags.

Verified

• The v0.3.0-rc.1 release build completed the full Hearth lifecycle on two physical NVIDIA A10 GPUs
  with vLLM v0.25.1, KEDA external-push, prewarming, 0→1→2→0, bounded admission, reject mode,
  graceful drain, component replacement, and host reboot recovery.
• Volcano v1.15.0 enforced queue placement and quota on Kind, then scheduled the real A10
  workloads through separate queues and placed two Hearth replicas on distinct whole GPUs.
• A Kthena-managed hot model and a Hearth-managed long-tail model served concurrently on the same
  host. Hearth recovered automatically after reboot; the documented Kthena device-admission race
  required manual Pod replacement and remains outside Hearth's controller boundary.

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🙏 Thanks to everyone who contributed to this release — the merged PRs and first-time
contributors are credited under What's Changed and New Contributors below.

Full Changelog: v0.2.0...v0.3.0