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

examples/sal/scripts/basics/hello.rhai

@@ -0,0 +1,39 @@
+// 01_hello_world.rhai
+// A simple hello world script to demonstrate basic Rhai functionality
+
+// Print a message
+println("Hello from Rhai!");
+
+// Define a function
+fn greet(name) {
+    "Hello, " + name + "!"
+}
+
+// Call the function and print the result
+let greeting = greet("SAL User");
+println(greeting);
+
+// Do some basic calculations
+let a = 5;
+let b = 7;
+println(`${a} + ${b} = ${a + b}`);
+println(`${a} * ${b} = ${a * b}`);
+
+// Create and use an array
+let numbers = [1, 2, 3, 4, 5];
+println("Numbers: " + numbers);
+println("Sum of numbers: " + numbers.reduce(|sum, n| sum + n, 0));
+
+// Create and use a map
+let person = #{
+    name: "John Doe",
+    age: 30,
+    occupation: "Developer"
+};
+
+println("Person: " + person);
+println("Name: " + person.name);
+println("Age: " + person.age);
+
+// Return a success message
+"Hello world script completed successfully!"