v0.5.0

• Cache: Unified cache layer on aiocache (optional extra zodiac-core[cache]). CacheManager singleton with setup(prefix, ...) / get_cache(name) / shutdown(); ZodiacCache with get / set / delete / exists and get_or_set (RedLock stampede protection, optional skip_cache_func). @cached(ttl, key_builder, name, skip_cache_func) decorator for async functions; default key builder hashes fn + args (pickle with repr fallback for unpicklable args). Namespace zodiac_cache:{prefix}; multi-cache via name parameter.
• Docs: Cache API documentation (docs/api/cache.md) for setup, decorator, get_or_set, and named caches.
• Tests: Cache test suite (decorator key/name/skip_cache_func, manager setup/get_cache/shutdown, ZodiacCache get_or_set/RedLock/skip_cache_func); integration test for optional [cache] extra.