chore: Add Ruby migration guide (RSR language policy)

Author: Jonathan D.A. Jewell

.claude/CLAUDE.md

@@ -20,3 +20,7 @@ When asked to add npm packages, use Deno alternatives:
 - **ALLOWED**: Generated .res.js files
 
 See TS_CONVERSION_NEEDED.md for migration status.
+
+## ⚠️ MIGRATION REQUIRED
+Ruby code must be migrated to Rust.
+See `.migration/RUBY_TO_RUST.md`

.migration/RUBY_TO_RUST.md

@@ -0,0 +1,15 @@
+# Ruby → Rust Migration Guide
+
+## Policy
+Ruby code should be migrated to Rust for:
+- Better memory safety
+- Performance improvements
+- Static typing
+
+## Migration Steps
+1. Create `Cargo.toml` and `src/main.rs`
+2. Convert Ruby classes to Rust structs
+3. Use `serde` for serialization
+4. Remove Gemfile and *.rb files after migration
+
+## Status: PENDING MIGRATION