fix(FN-2139): wire source export condition into CLI builds

- Add "source" export entries for @fusion/core, @fusion/dashboard, and @fusion/engine package exports
- Configure tsup/esbuild to include the "source" condition when resolving workspace dependencies
- Pass --conditions=source to bun compile so compiled CLI binaries resolve source-conditioned exports consistently

packages/dashboard/package.json

@@ -5,6 +5,7 @@
   "exports": {
     ".": {
       "types": "./src/index.ts",
+      "source": "./src/index.ts",
       "import": "./dist/index.js"
     },
     "./planning": {