feat(valkey): initial stable release v0.9.0

Valkey (Redis-compatible) client component with launcher lifecycle and health check integration.

What's included:
- Config with Addrs, Password, SelectDB, CacheSizeEachConn (env-driven)
- Provider interface exposing native valkey-go Client() directly (no wrapper)
- Component interface: launcher.Component + health.Checkable + Provider
- New(logger, cfg) constructor for lifecycle registration via lc.Append
- Health check via PING at LevelDegraded priority
- Graceful shutdown calling client.Close() in OnStop

Tested-via: todo-api POC integration
Reviewed-against: docs/adr/

go.mod

@@ -0,0 +1,12 @@
+module code.nochebuena.dev/go/valkey
+
+go 1.25
+
+require (
+	code.nochebuena.dev/go/health v0.9.0
+	code.nochebuena.dev/go/launcher v0.9.0
+	code.nochebuena.dev/go/logz v0.9.0
+	github.com/valkey-io/valkey-go v1.0.54
+)
+
+require golang.org/x/sys v0.29.0 // indirect