docs: make browser installation substrate-aware

docs/get-started/first-workflow.md

@@ -10,23 +10,23 @@ and RDP or Citrix sessions by choosing a
 ## Prerequisites
 
 - **Python 3.10-3.12.** The engine declares `requires-python >=3.10,<3.13`.
-- **macOS, Linux, or Windows.** This walkthrough uses the Playwright-driven
-  Chromium browser, the default backend, so it has no OS-specific steps. The browser
-  provisions automatically the first time you record or replay; to provision it
-  ahead of time, run `playwright install chromium`.
+- **macOS, Linux, or Windows.** This walkthrough selects the Playwright-driven
+  browser capability, so it has no OS-specific steps. Its matching Chromium
+  provisions automatically on the first web action; native, RDP, and Citrix
+  paths do not install it.
 
 Install the CLI if you have not already:
 
 ```bash
-pip install openadapt
+pip install 'openadapt[browser]'
 ```
 
 Or use the installer script from the landing page, which installs
 [uv](https://docs.astral.sh/uv/) if needed and sets up a persistent
 `openadapt` command:
 
 ```bash
-curl -fsSL https://openadapt.ai/install.sh | sh
+curl -fsSL https://openadapt.ai/install.sh | sh -s -- browser
 ```
 
 No web app of your own to record against? No setup needed:

docs/get-started/index.md

@@ -9,22 +9,35 @@ data boundary.
 ## Install
 
 ```bash
-pip install openadapt
+pip install 'openadapt[browser]'
 ```
 
-The default backend is a headless browser. The first time you record or
-replay against a web app, the browser provisions automatically. To provision it
-ahead of time:
+This walkthrough selects the browser capability explicitly. Playwright is not
+part of the lightweight base runtime used by native desktop, RDP, or Citrix
+workflows. The first time you record or replay a web app, the matching Chromium
+build provisions automatically. To provision it ahead of time:
 
 ```bash
 playwright install chromium
 ```
 
-The public install and command path is `pip install openadapt` followed by
-`openadapt flow <verb>`. Contributors who work on the engine directly can use
+The public package and command path remains `openadapt` followed by `openadapt
+flow <verb>`; extras select only the substrate dependencies you need.
+Contributors who work on the engine directly can use
 the standalone [`openadapt-flow`](https://github.com/OpenAdaptAI/openadapt-flow)
 package; it is not a second end-user onboarding path.
 
+For native or remote-only work, keep the base install and add only the selected
+driver:
+
+```bash
+pip install openadapt
+pip install 'openadapt[capture,windows]'  # example: native Windows
+pip install 'openadapt[capture,rdp]'      # example: network RDP
+```
+
+Neither path installs or downloads Chromium.
+
 ## The complete demo journey
 
 ```bash

docs/reference/configuration.md

@@ -53,6 +53,12 @@ egress for the deployed image. See
 
 ## Browser provisioning
 
+Browser support has two intentionally separate layers. Install the Playwright
+driver only for web workflows with `pip install 'openadapt[browser]'`. The
+matching Chromium build downloads lazily on the first web action. Native
+desktop, RDP, and Citrix commands neither import Playwright nor trigger a
+browser download.
+
 | Variable | Purpose |
 |---|---|
 | `OPENADAPT_FLOW_NO_AUTO_INSTALL` | Disables automatic browser provisioning. Set it when you manage the browser yourself (e.g. you ran `playwright install chromium` ahead of time in a controlled image). |