[moetemp]

What changed?

This PR adds the memory Store and the shared Store suite.

• The memory Store keeps the Redis layout and runs the steps of the Lua scripts in the same order.
• The suite is in testing, behind the test-support feature, so the Redis crate runs the same cases. The name of each case says the guarantee it checks, and a failed run lists the cases that failed.
• DEFAULT_RETENTION and DEFAULT_SAFETY_TTL give every Store the same defaults.
• A create of an expired, other-owner or closed Stream fails with stream_expired, stream_not_owner or stream_closed. A Workflow's create doesn't take a client's Stream. A create of an open Stream fails with stream_already_exists, unless it uses the Stream or retries the create that made it, which the Store knows by the request id that it keeps.
• A Stream with no owner takes a close from a Workflow or a client. A close writes no entry, and it wakes the waiting reads.
• Stored data that isn't valid fails with stream_storage_corrupt, which a retry can't fix.
• Each append removes the fence and dedupe fields of up to 64 Producers whose last append is older than the Retention, from the producers set. So the meta keeps the Producers of about one Retention.
• An open Workflow Stream's meta keeps the safety TTL, but its log expires one Retention after the last write, since a read hides every Record by then. The meta's newest keeps the next offsets above the old ones. A write after the log expired raises trimmed to newest, so a Reader behind it gets stream_expired.
• No retry run or orphan rules yet, so no RUN_FENCE. K7 adds them.

Depends on #214 (K3). Review lane is the Redis and Lua reviewers, as the reference for R1 and R2 (temporal-community/sdk-streams#1 and #2).
Part of the Brook review series.

Why?

The same rules exist in Lua, in this Store, in gen_vectors.py and in the Jetty server. Plain Rust is easier to check first, and the suite fails when two Stores differ.

How did you test it?

cargo fmt, cargo clippy -- -D warnings (with and without features), cargo test -p temporalio-streams --all-features and cargo doc pass at this commit. The suite runs on the memory Store here, and on Redis in R1.

[moetemp]

Closed in favor of #228, the combined branch, which has this change.