Add claude docs

.claude/script.md

@@ -0,0 +1,167 @@
+# Script System (JerryScript)
+
+Source: `src/dusk/script/`, modules at `src/dusk/script/module/`
+
+## Overview
+
+The engine embeds **JerryScript** as its scripting runtime. Game scenes
+and logic are authored in JavaScript (ES5 subset). The script system
+initialises JerryScript, registers all built-in C modules as JS globals,
+and runs the event loop each tick.
+
+The full rules for writing JS asset scripts are in `CLAUDE.md` under
+"JavaScript (asset scripts)". This doc covers the C-side module system.
+
+## Script lifecycle
+
+```c
+errorret_t scriptInit();    // start JerryScript, register all modules
+errorret_t scriptUpdate();  // run pending microjobs (call once per frame)
+errorret_t scriptDispose(); // shut down JerryScript
+
+errorret_t scriptExecString(const char_t *source);
+// Evaluate a JS source string in global scope.
+
+errorret_t scriptExecFile(const char_t *path);
+// Load + eval a script from the asset archive. Result cached by asset
+// system -- repeated calls with the same path do not re-execute.
+```
+
+## Module registration
+
+All C modules are initialised in `src/dusk/script/module/modulelist.c`:
+
+```c
+void moduleListInit(void);    // called by scriptInit
+void moduleListDispose(void); // called by scriptDispose
+```
+
+Each module's `Init` is called once. The module registers its
+properties and methods on `scriptproto_t` objects (see below), which
+become JS globals.
+
+## Writing a C module -- the `scriptproto_t` pattern
+
+A `scriptproto_t` represents a JS class prototype backed by a C struct.
+
+### 1. Declare in the header
+
+```c
+// moduleMything.h
+extern scriptproto_t MODULE_MYTHING_PROTO;
+
+// Init and dispose for the module itself:
+void moduleMyThingInit(void);
+void moduleMyThingDispose(void);
+```
+
+### 2. Implement
+
+```c
+// moduleMything.c
+scriptproto_t MODULE_MYTHING_PROTO;
+
+// JS-callable function using the convenience macro:
+moduleBaseFunction(myThingDoSomething) {
+  moduleBaseRequireArgs(1);
+  moduleBaseRequireNumber(0);
+  float_t x = moduleBaseArgFloat(0);
+  // ... do work ...
+  return jerry_undefined();
+}
+
+void moduleMyThingInit(void) {
+  scriptProtoInit(
+    &MODULE_MYTHING_PROTO,
+    "MyThing",    // JS global name; NULL to skip registration
+    sizeof(mything_t),
+    myThingCtor   // constructor handler, or NULL
+  );
+
+  // Instance methods:
+  scriptProtoDefineFunc(
+    &MODULE_MYTHING_PROTO, "doSomething", myThingDoSomething
+  );
+
+  // Instance property (get/set):
+  scriptProtoDefineProp(
+    &MODULE_MYTHING_PROTO, "x", myThingGetX, myThingSetX
+  );
+
+  // Static method:
+  scriptProtoDefineStaticFunc(
+    &MODULE_MYTHING_PROTO, "create", myThingCreate
+  );
+}
+```
+
+### 3. Register
+
+In `modulelist.c`: `#include` the header and call `moduleMyThingInit()`
+in `moduleListInit()` (and `Dispose` in `moduleListDispose()`).
+
+## `moduleBaseFunction` macro
+
+```c
+moduleBaseFunction(myFn) {
+  // callInfo, args[], argc available
+  moduleBaseRequireArgs(2);
+  moduleBaseRequireNumber(0);
+  moduleBaseRequireString(1);
+
+  float_t x = moduleBaseArgFloat(0);
+  int32_t n = moduleBaseArgInt(0);
+  bool_t  b = moduleBaseArgBool(0);
+  float_t opt = moduleBaseOptFloat(2, 0.0f);  // optional with default
+
+  // Error propagation:
+  errorret_t ret = someCall();
+  if(errorIsNotOk(ret)) return moduleBaseThrowError(ret);
+
+  return jerry_undefined();    // or jerry_boolean(true) etc.
+}
+```
+
+## Wrapping C values in JS objects
+
+```c
+// Create a JS object wrapping a copy of a C value:
+jerry_value_t obj = scriptProtoCreateValue(&MY_PROTO, &myValue);
+
+// Unwrap back to C pointer:
+mything_t *ptr = scriptProtoGetValue(&MY_PROTO, jsObj);
+// ptr is NULL if jsObj is not an instance of MY_PROTO.
+```
+
+## Utility helpers (`modulebase.h`)
+
+| Helper | Purpose |
+|--------|---------|
+| `moduleBaseThrow(msg)` | Return a JS TypeError |
+| `moduleBaseThrowError(ret)` | Convert `errorret_t` -> JS error |
+| `moduleBaseToString(val, buf, len)` | Jerry value -> C string |
+| `moduleBaseGetProp(obj, name)` | Get object property by name |
+| `moduleBaseWrapPointer(ptr)` | Wrap a raw pointer in a JS object |
+| `moduleBaseUnwrapPointer(val)` | Unwrap a raw pointer |
+| `moduleBaseSetValue(name, val)` | Set a global JS variable |
+| `moduleBaseSetNumber(name, n)` | Set a global JS number |
+| `moduleBaseSetInt(name, n)` | Set a global JS integer |
+| `moduleBaseDefineMethod(obj, name, fn)` | Add method to any JS object |
+| `moduleBaseDefineGlobalMethod(name, fn)` | Add method to global scope |
+
+## Async JS -- pending promises (`scriptpromisepend.h`)
+
+When a C module needs to resolve a JS `Promise` from an asynchronous
+C event, use `scriptpromisepend_t`. Each module declares a fixed-size
+pending slot array; the helpers add/resolve/reject by an opaque key.
+
+Full API and design notes: `.claude/script-promises.md`
+
+## Type declarations (`.d.ts`)
+
+Every module that is accessible from JS **must** have a corresponding
+TypeScript declaration file in `types/`. The CLAUDE.md checklist
+requires updating these whenever a `.c` module file changes.
+
+- Add `types/<category>/mymod.d.ts`
+- Add `/// <reference path="..." />` to `types/index.d.ts`