[moetemp]

This PR counts a Stream's Retention from its close in the Redis Store, as a namespace's Retention
does. An open Stream also keeps every Producer's dedupe and fence state.

A Stream that stayed open longer than its Retention lost its first Records. Each append ran XTRIM
on the Records older than the Retention, and the log expired one Retention after the last write.
The log now expires at exp, so an open Stream keeps every Record. It expires only if the Store config sets
last_write_ttl, that long after its last write. A closed Stream still expires one Retention after the close.

No append drops a Producer's p| field by its age either. So a resend of a silent Producer's last
batch gets the first answer, a read never gets a second copy, and a lower epoch of the Producer
stays fenced. The state goes only with the Stream, at the cost of one 88-byte p| field for each
Producer that wrote to it.

• trim is now mark_log_gone. It only raises trimmed when a write finds the log gone, as after
  an eviction.
• prune and the :producers key are gone, since nothing else read the key. The write scripts take
  two keys, and a Producer no longer needs +xtrim, +zadd, +zrangebyscore or +zrem.
• scripts/patch-sdk-rust.sh builds against 5a5f856f of Streams crate: combined branch for review moetemp/sdk-rust#228, which makes the same
  changes in the memory Store and the shared suites.
• The meta hash has no closer and cstat, since a read gives only Records and tells of a close
  with done.
• The test runtime sets a 300 s last_write_ttl, since an open Stream keeps the suites' Records
  until it expires.

Two later commits follow the Stream crate's changes of Nov. 10.

• last_write_ttl replaces the safety TTL and has no default. A write with no TTL clears an expiry
  that an earlier write set, so a Producer needs +hdel and +persist.
• The Store's read and wait calls take a StreamRef, as the other calls do.
• The keys have no Temporal namespace. They are <prefix>:{<stream id>}:meta, :log and :closed,
  so a Stream id is unique in one Redis and key prefix. An ACL key pattern now scopes a user to a
  prefix, and docs/redis.md says so.

Two more commits follow the Stream crate's changes of Nov. 11. A read has no create_wait, a write names
its Producer directly, and each read item carries its own offset. The Redis Store needed no change for
them beyond its pin and its tests.

The last commits follow the crate's new shape of Nov. 11.

• The runtime builds on the crate's LazyStore, which connects on the first call that needs Redis. So
  a bridge can build the runtime with Redis down, and the first call then fails with
  stream_storage_unavailable.
• The API has no UNKNOWN_WRITER reason, so the three reasons after it have new numbers.

The last three commits follow the crate's restart of Nov. 12. The crate now keeps only what answers
the five Stream operations.

• The crate has no writer objects, so the writer suite and tests/writer.rs are gone. A bridge calls
  StreamRuntime::call with an operation name and the encoded request.
• store_name replaces backend in RedisStreamConfig and in RuntimeOptions, as StreamRef.store
  does in the API.
• A Producer id is opaque text of at most 4096 bytes, and the p| field takes its bytes as they are.
  The Store keeps a Producer's fence by kind and id, so the id of a run-based kind must hold its run
  id. docs/redis.md says so.
• The shared suites have new cases, and Redis passes them: two runs with their own ids, two kinds
  with one id, an id of any text, and a close by each Producer kind.