fix: respect AGENT_BROWSER_HEADED env var for headed mode (#92)

The headless option was hardcoded to true in the auto-launch section,
ignoring the AGENT_BROWSER_HEADED environment variable. This fix checks
the env var so users can run the browser in headed mode by setting
AGENT_BROWSER_HEADED=1.

Fixes #90

src/daemon.ts

@@ -200,7 +200,7 @@ export async function startDaemon(options?: { streamPort?: number }): Promise<vo
             await browser.launch({
               id: 'auto',
               action: 'launch',
-              headless: true,
+              headless: process.env.AGENT_BROWSER_HEADED !== '1',
               executablePath: process.env.AGENT_BROWSER_EXECUTABLE_PATH,
               extensions: extensions,
             });