Redis L2 shared-cache storage driver for Agent Assembly.

This crate implements three of the high-frequency [aa_storage] traits against a Redis (or Valkey) instance so multiple Assembly processes can coordinate through one shared cache instead of each hitting the L3 store:

• [RedisSessionStore] — SessionStore
• [RedisRateLimitCounter] — RateLimitCounter
• [RedisPolicyStore] — PolicyStore, used as a read-through cache in front of the authoritative store

Build a [RedisBackend] from a [RedisStorageConfig] and hand out the individual stores, or construct each store directly over a shared [Pool].

Key layout

Every key is namespaced under aa::

<session_id> and <agent_id> are the lower-case hex encodings of the 16-byte ids.

TTL and invalidation semantics

• Sessions expire after [SESSION_TTL_SECS] seconds. The TTL is re-armed on every save so an actively written session never lapses; delete drops it immediately and is idempotent.
• Rate-limit counters carry the window length supplied to increment as their TTL. The expiry is armed exactly once — on the first increment that creates the key — so the window is fixed: it starts at the first hit and is not pushed forward by later increments within the same window. reset deletes the key.
• Policies are cached with an explicit per-entry TTL via [RedisPolicyStore::cache_policy] ([DEFAULT_POLICY_CACHE_TTL_SECS] is the suggested default). invalidate deletes the cached key so the next read misses and reloads from the authoritative store; it is idempotent.