Spooky 0.4.0-beta — Runtime Lifecycle & Canonical Observability

Minor release covering all changes since 0.3.1-beta.

Added

Deterministic runtime lifecycle state machine — reload commits, drain, and shutdown now flow through explicit lifecycle states rather than ad-hoc paths, making generation swaps predictable under load.
Canonical observability vocabulary — admission outcomes, local reason enums, overload metric labels, and backend health-failure reasons all map to one canonical set, with bounded connect-attempt label cardinality to keep metric series stable.
Unified backend refresh classification — DNS/health refreshes report explicit traffic-continuity outcomes, and the canonical backend health-failure reason is surfaced in the control-plane snapshot.
Structured reload rejections — operator-facing reload preflight failures now carry structured messages, backed by a typed operational-policy vocabulary for runtime ownership and reload rules.
Live log-level reload — log.level changes apply on config reload via a runtime set_log_level, no restart required.

Process-shared watchdog and DNS resolver are now carried across reload instead of being rebuilt, preserving state through generation swaps.
Bundle-lock panic and control-API unreachable paths replaced with fail-safe recovery; backend client-rotation failure is now an explicit, operator-visible outcome.
Pre-response requests still reading the body now time out under the request-body bucket.
Restored stateful round-robin selection, failover availability on circuit-open retries, and streaming guardrail failure semantics.
WebSocket upgrade headers preserved in bootstrap 101 responses.
Upstreams iterated in name order so route conflicts report deterministically.

Public API surface locked down across all crates — crate-internal items demoted, unreachable_pub enforced, dead code removed, and public runtime/listener/connection surfaces documented.
Documentation realigned to the post-refactor architecture (edge runtime ownership, runtime generation & backend lifecycle, request lifecycle, transport boundaries, observability, and reload behavior).
Test suite hardened with per-contract cases asserting QUIC/bootstrap parity, metric label vocabularies, and retry/hedge accounting.