Remove $ syntax handling and related tests

* **src/index.ts**
  - Remove `$` syntax handling from `getExe` and `exeOp` functions
  - Bump version to 241030

* **src/web.ts**
  - Remove `$` syntax handling from `set`, `get`, and `exe` functions

* **README.md**
  - Remove mention of `$` get/set syntax from "Coding in Insitux" section
  - Remove example using `$` syntax from "Various examples" section
  - Remove advisory for integration support of `$`

* **package.json** and **package-lock.json**
  - Bump version to 24.10.30

* **src/test.ts**
  - Remove tests related to `$`

src/test.ts

@@ -1,7 +1,19 @@
 import { concat, round, getTimeMs, len, padEnd, trim } from "./poly-fills";
 import { Ctx, Env, Val, ValOrErr, InvokeResult } from "./types";
 
-type State = { output: string };
+type State = { dict: Map<string, Val>; output: string };
+
+function get(state: State, key: string): ValOrErr {
+  if (!state.dict.has(key)) {
+    return { err: `"${key}" not found.` };
+  }
+  return state.dict.get(key)!;
+}
+
+function set(state: State, key: string, val: Val): string | undefined {
+  state.dict.set(key, val);
+  return undefined;
+}
 
 function exe(state: State, name: string, args: Val[]): ValOrErr {
   const nullVal: Val = { t: "null", v: undefined };
@@ -552,11 +564,16 @@ export function doTests(
   }[] = [];
   for (let t = 0; t < len(tests); ++t) {
     const { name, code, err, out } = tests[t];
-    const state: State = { output: "" };
+    const state: State = {
+      dict: new Map<string, Val>(),
+      output: "",
+    };
     const env: Env = { funcs: {}, vars: {}, mocks: {} };
     const startTime = getTimeMs();
     const valOrErrs = invoke(
       {
+        get: (key: string) => get(state, key),
+        set: (key: string, val: Val) => set(state, key, val),
         print: (str, withNewLine) => {
           state.output += str + (withNewLine ? "\n" : "");
         },