feat(cpp.js): export.bundle flag to skip wasm bundle emit

New `export.bundle` boolean (default `true`) lets a package opt out of
the final emcc link step. When `false`, the WASM target still produces
its `.a` archives (consumed by other packages or by native iOS/Android
builds via xcframework / .so) but the `.wasm` + `.js` glue and the
Bridge-stage compile are skipped entirely.

Useful for:
- mobile-only apps that consume cpp.js via iOS/Android pipelines
- library packages whose WASM output exists only to be linked into a
  downstream app's bundle

Guarded in three layers:
- `createWasmJs` (bin.js): short-circuits the whole WASM pipeline
  before bridge discovery / Bridge compile / emcc / copy
- `buildWasm` (action): defence-in-depth for callers that bypass the
  CLI (rollup/vite plugins)
- `loadConfig`: default `true`, `??` not `||` so explicit `false`
  survives

Has no effect on iOS/Android pipelines, which never produce a bundle.
Bumps cpp.js to beta.18.

Author: bugra9

cppjs-core/cpp.js/package.json

@@ -1,6 +1,6 @@
 {
     "name": "cpp.js",
-    "version": "2.0.0-beta.17",
+    "version": "2.0.0-beta.18",
     "license": "MIT",
     "homepage": "https://cpp.js.org",
     "repository": "https://github.com/bugra9/cpp.js.git",

cppjs-core/cpp.js/src/actions/buildWasm.js

@@ -12,6 +12,13 @@ export default async function buildWasm(target, options = {}) {
     const isProd = target.buildType === 'release';
     const buildType = isProd ? 'Release' : 'Debug';
 
+    // Caller can opt out of the final emcc link entirely (e.g. when the
+    // package is consumed only as a static library by downstream builds).
+    if (state.config.export.bundle === false) {
+        logger.info(`[${target.path}] wasm+js skipped (export.bundle = false)`);
+        return;
+    }
+
     if (!options.force && fs.existsSync(`${state.config.paths.build}/${target.jsName}`) && fs.existsSync(`${state.config.paths.build}/${target.wasmName}`)) {
         logger.cachedStep(target, 'wasm+js');
         return;

cppjs-core/cpp.js/src/bin.js

@@ -325,6 +325,9 @@ function buildLib(targetParams) {
 }
 
 async function createWasmJs(targetParams) {
+    if (state.config.export.bundle === false) {
+        return;
+    }
     const targets = getFilteredBuildTargets(targetParams, { platform: 'wasm' });
     if (targets.length === 0) {
         return;

cppjs-core/cpp.js/src/state/loadConfig.js

@@ -90,6 +90,7 @@ function getFilledConfig(config, options = { isDepend: false }) {
     newConfig.export.libPath = getPath(newConfig.export.libPath || 'lib');
     newConfig.export.libName = newConfig.export.libName || [newConfig.general.name];
     newConfig.export.binHeaders = newConfig.export.binHeaders || [];
+    newConfig.export.bundle = newConfig.export.bundle ?? true;
 
     newConfig.allDependencies = (() => {
         const output = {};