HydraCache 0.33.0

0.33.0 focuses on production ergonomics after the 0.32.0 database adapter
parity release.

Planned Highlights

Policy presets for common cache intent: short-lived values, read-mostly
values, per-entity values, explicit-invalidation-only values, and negative
cache entries.
Refresh/stale options for serving recently expired values while a reload is
running or when a loader temporarily fails.
Shared database-neutral refresh behavior for SQLx, Diesel, SeaORM, and custom
repository loaders.
Production guidance for keys, tags, TTLs, stale behavior, invalidation, and
observability.
Soft cleanup tooling for generated release/test target directories.

Added QueryCachePolicy and PreparedQueryPolicy presets:
short_lived, read_mostly, per_entity,
no_ttl_explicit_invalidation, and negative_cache.
Added PreparedQueryPolicy::cache_entity::<T>() so prepared presets can be
combined with HydraCacheEntity metadata without rebuilding the policy from
scratch.
Added RefreshOptions and HydraCache::get_or_load_with_refresh for
refresh_ahead, stale_while_revalidate, and bounded
stale_on_loader_error behavior on local loader-based cache reads.
Added database-neutral RefreshPolicy support on QueryCachePolicy,
PreparedQueryPolicy, DbQuery, and adapter re-exports so SQLx, Diesel,
SeaORM, and custom repository loaders share the same stale/refresh behavior.
Added docs/PRODUCTION_GUIDE.md for keys/tags, presets, refresh behavior,
invalidation safety, and observability guidance.
Added scripts/clean-generated-targets.ps1 for safely removing generated
release/check target directories without a full cargo clean.
Reduced one refresh-path allocation by checking stale-window eligibility
before cloning expired entries for error fallback.

This release should pass: