feat: reorganize examples and add signature support to JobBuilder

- Reorganized examples into osiris/, sal/, and utils/ folders
- Moved hardcoded scripts to separate .rhai files
- Added signature() method to JobBuilder for job signing
- Updated OSIRIS context to use block_in_place instead of runtime
- Removed runtime field from OsirisContext
- Added typed save() methods for Note and Event objects
- Updated all examples to use new structure and APIs

src/engine/mod.rs

@@ -2,16 +2,13 @@
 /// 
 /// This module provides two different engine configurations:
 /// - `system`: SAL modules for system operations (async worker)
-/// - `osis`: DSL modules for business operations (sync worker)
-/// - `osiris`: DSL modules for business operations (sync worker)
+/// - `osis`: OSIRIS engine for business operations (sync worker)
 
 pub mod system;
 pub mod osis;
-pub mod osiris;
 
 pub use osis::create_osis_engine;
 pub use system::create_system_engine;
-pub use osiris::{create_osiris_engine, run_osiris_script};
 
 // Re-export common Rhai types for convenience
 pub use rhai::{Array, Dynamic, Engine, EvalAltResult, Map};