Refactor Rhai integration with context-based execution and type registry

Major Changes:
- Moved Rhai support from rhai_support/ to rhai/ module
- Implemented context-based execution with signatory access control
- Added TypeRegistry for dynamic type registration and object creation
- Refactored engine to use context (Vec<String>) instead of instance
- Removed old runner binary (moved to runner_rust crate)

Rhai Module:
- engine.rs: Core Rhai engine with context-based get_context()
- functions.rs: Rhai function bindings (create_note, create_event, etc.)
- mod.rs: Module exports and organization

Store Improvements:
- TypeRegistry for registering object types and creators
- Generic store uses type registry for dynamic object creation
- Improved error handling and type safety

Documentation:
- RHAI_REFACTOR_COMPLETE.md: Refactoring details
- SIGNATORY_ACCESS_CONTROL.md: Context-based access control
- TYPE_REGISTRY_DESIGN.md: Type registry architecture
- REFACTORING_COMPLETE.md: Overall refactoring summary
- TESTS_COMPLETE.md: Testing documentation

Build Status: ✅ Compiles successfully with minor warnings

src/store/object_trait.rs

@@ -41,6 +41,11 @@ pub trait Object: Debug + Clone + Serialize + for<'de> Deserialize<'de> + Send +
         &self.base_data().id
     }
     
+    /// Set the unique ID for this object
+    fn set_id(&mut self, id: impl ToString) {
+        self.base_data_mut().id = id.to_string();
+    }
+    
     /// Get the namespace for this object
     fn namespace(&self) -> &str {
         &self.base_data().ns