Start CQRS refactoring: Create Osiris client crate

- Added workspace structure to Osiris Cargo.toml
- Created osiris-client crate for query operations (GET requests)
- Implemented generic get(), list(), query() methods
- Added KYC, payment, and communication query modules
- Created comprehensive refactoring plan document

CQRS Pattern:
- Commands (writes) → Supervisor client → Rhai scripts
- Queries (reads) → Osiris client → REST API

Next steps:
- Implement Osiris server with Axum
- Restructure SDK client by category (kyc/, payment/, etc.)
- Update FreezoneClient to use both supervisor and osiris clients

Cargo.toml

@@ -1,3 +1,11 @@
+[workspace]
+members = [
+    ".",
+    "client",
+    "server",
+]
+resolver = "2"
+
 [package]
 name = "osiris"
 version = "0.1.0"