Add redis keyvalue plugin support

[jfleitz]

Add Redis backend for wasi:keyvalue and redis-keyvalue example

Summary

• Implements a Redis-backed wasi:keyvalue plugin (RedisKeyValue) in wash-runtime using the redis crate with a multiplexed async connection. Keys are namespaced per bucket as {identifier}:{key}.
• Adds wasi_keyvalue_redis_url to DevConfig so projects can opt into the Redis backend via .wash/config.yaml.
• Wires the Redis backend into wash dev with priority order: Redis → filesystem → in-memory.
• Adds a new examples/redis-keyvalue project — an HTTP component that stores and retrieves key-value pairs through the wasi:keyvalue/store interface, backed by Redis at runtime.

Changes

Area	What changed
crates/wash-runtime	New redis.rs plugin; RedisKeyValue::from_url constructor; redis workspace dep
crates/wash/src/config.rs	DevConfig.wasi_keyvalue_redis_url: Option<String>
crates/wash/src/cli/dev.rs	Redis branch in keyvalue plugin selection
examples/redis-keyvalue/	New self-contained example component with WIT deps, config, and README

Testing

Testing was completed by running a Redis server locally via Docker:

docker run --name redis -p 6379:6379 redis:latest

The example was built and run with wash dev from the examples/redis-keyvalue/ directory. The following curl commands were used to validate correct behaviour:

# Store a key-value pair
curl -X POST http://localhost:8000 \
  -H "Content-Type: application/json" \
  -d '{"key":"mykey","value":"myvalue"}'
# → 200 Stored key 'mykey'

# Retrieve the value
curl "http://localhost:8000?key=mykey"
# → 200 myvalue

# Retrieve a key that does not exist
curl "http://localhost:8000?key=missing"
# → 404 Key 'missing' not found

Signed-off-by: Jeremy Fleitz jeremy@cosmonic.com

[lxfontes]

Logic wise this is fine, however can we use MGET?

One big redis roundtrip vs many small ones.

The code we have for v1 is for wrpc-bindgen so slightly different signatures https://github.com/wasmCloud/wasmCloud/blob/main/crates/provider-keyvalue-redis/src/lib.rs#L465

[lxfontes]

This is 99% ✅ 🎉
The only real blocker is the loss of precision u64 -> i64

[jfleitz]

Made updates to use MGET and MSET. I also added a check for u64 numbers that would be truncated/wrapped so that it still meets the WIT spec, but would throw an error if too large.

Retested with the example/redis-keyvalue project.