docs: add SETUP.md for Agentic Inner Loop KPI [PLT-103741] (#507)

* docs: add SETUP.md for Agentic Inner Loop KPI [PLT-103741]

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* docs: cap Node heap in SETUP.md build command to avoid CI OOM [PLT-103741]

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: Sarath1018

SETUP.md

@@ -0,0 +1,137 @@
+# SETUP.md
+
+Machine-executable setup, build, and test instructions for the UiPath TypeScript SDK.
+
+## Prerequisites
+
+- Node.js 20+ (npm 10+ is bundled)
+- git
+
+### Supported platforms
+
+- [x] Linux
+- [x] macOS
+- [ ] Windows
+
+## Environment Variables
+
+### Standard (injected by pipeline)
+
+| Variable | Description |
+|----------|-------------|
+| `GITHUB_TOKEN` | Referenced by this repo's `.npmrc` (`//npm.pkg.github.com/:_authToken=${GITHUB_TOKEN}`). All dependencies resolve from the public npm registry via `package-lock.json`, so the token value is never validated during install — it only needs to be set so npm can interpolate the `.npmrc`. Any non-empty value works for local dev. |
+
+### Project-specific
+
+None. Unit tests are fully mocked and need no credentials or external infrastructure. (Integration tests against a live UiPath tenant exist under `tests/integration/` but are not part of this loop.)
+
+## Setup
+
+```bash
+# .npmrc interpolates ${GITHUB_TOKEN}; default it for local dev (pipeline injects the real one).
+export GITHUB_TOKEN="${GITHUB_TOKEN:-local-dev-placeholder}"
+
+# Install exact locked dependencies.
+npm ci --no-audit --no-fund
+```
+
+## Verify Setup
+
+```bash
+node --version
+npm ls rollup vitest typescript --depth=0
+```
+
+`node --version` confirms Node 20+ is on PATH; `npm ls` exits non-zero if the build/test toolchain failed to install.
+
+## Build
+
+```bash
+# The .d.ts bundling across ~20 subpath modules peaks above Node's default heap
+# cap on 7GB CI agents — grant 4GB explicitly to avoid an OOM abort.
+NODE_OPTIONS="--max-old-space-size=4096" npm run build
+```
+
+Runs rollup and emits ESM, CJS, UMD bundles and `.d.ts` files per module into `dist/`.
+
+## Test
+
+```bash
+npm run test:unit
+```
+
+Runs the full vitest unit suite (no network, no credentials required).
+
+## Sample Code Change
+
+### The change
+
+Add a new exported function `filterNullish` to `src/utils/object.ts` — the symmetric complement of the existing `filterUndefined` (which removes only `undefined` values), removing both `null` and `undefined`. Append at the end of the file:
+
+```typescript
+/**
+ * Filters out null and undefined values from an object
+ * @param obj The source object
+ * @returns A new object without null or undefined values
+ */
+export function filterNullish<T extends Record<string, any>>(obj: T): Partial<T> {
+  const result: Partial<T> = {};
+
+  for (const [key, value] of Object.entries(obj)) {
+    if (value !== null && value !== undefined) {
+      result[key as keyof T] = value;
+    }
+  }
+
+  return result;
+}
+```
+
+Then create a new test file `tests/unit/utils/object.test.ts` with exactly this content:
+
+```typescript
+import { describe, it, expect } from 'vitest';
+import { filterNullish } from '@/utils/object';
+
+describe('filterNullish', () => {
+  it('removes null and undefined values', () => {
+    expect(filterNullish({ a: 1, b: undefined, c: null, d: 'x' })).toEqual({ a: 1, d: 'x' });
+  });
+
+  it('returns an equal object when no nullish values are present', () => {
+    expect(filterNullish({ a: 1, b: 'x', c: false, d: 0 })).toEqual({ a: 1, b: 'x', c: false, d: 0 });
+  });
+});
+```
+
+Do not modify any existing function, export, or test.
+
+### Verification
+
+```bash
+npx vitest run tests/unit/utils/object.test.ts
+npm run typecheck
+```
+
+## Troubleshooting
+
+### `npm error Failed to replace env in config: ${GITHUB_TOKEN}`
+
+Older npm versions fail hard when `.npmrc` references an unset variable. Set it to any non-empty value: `export GITHUB_TOKEN=local-dev-placeholder`.
+
+### Build aborts with `FatalProcessOutOfMemory` / `JavaScript heap out of memory`
+
+Node's default heap cap is below the build's peak memory on machines with ~7GB RAM (typical hosted CI agents). Re-run with an explicit 4GB heap: `NODE_OPTIONS="--max-old-space-size=4096" npm run build`.
+
+### `vitest: command not found` / `rollup: command not found`
+
+Dependencies are not installed — run `npm ci` from the repo root and invoke tools through npm scripts (`npm run build`, `npm run test:unit`) or `npx`.
+
+## Architecture
+
+- `src/core/` — UiPath client, auth (OAuth + secret-based), config, errors, HTTP client, telemetry
+- `src/services/` — typed service clients per platform area (Action Center, Conversational Agent, Data Fabric, Maestro, Orchestrator)
+- `src/models/` — TypeScript interfaces/types per service domain
+- `src/utils/` — constants, pagination, encoding, HTTP helpers
+- `tests/unit/` — vitest unit tests (mocked, no network); `tests/integration/` — live-API tests, excluded from this loop
+- Build is rollup-based (`rollup.config.js`); each service is published as a separate subpath export