Remove the embedded Environment Browser

[laotoutou]

What

• Remove the Browser Inspector tab, human/agent ownership UI, Playwright Dashboard and VNC proxying, Browser HTTP/WebSocket APIs, and Browser AppService provisioning.
• Keep official playwright-cli detection and version-matched Agent Skill materialization without downloading or starting a browser.
• Keep Sandbox loopback URLs inert until a dedicated Preview surface exists.
• Regenerate the OpenAPI contract and update public docs, managed-skill guidance, unit coverage, and E2E expectations.

Why

The current Environment Browser combines two different product responsibilities: previewing services inside the Sandbox and sharing an interactive browser between a human and an agent. That coupling also pulls the Playwright Dashboard, headed-browser/VNC takeover, browser ownership, and profile recovery into one lifecycle. Removing this path establishes a clean boundary before Preview and Browser return as independent tabs.

Impact

• New Environments no longer provision the sandpi-browser-dashboard AppService.
• The pre-1.0 /api/v1/environments/{environmentId}/browser... surface is removed.
• Inspector tabs are now Files, Activity, and Metrics.
• Playwright remains available to agents when the Environment provides a compatible browser executable separately.
• Companion coding-agent image cleanup: Remove Chrome from the coding-agent image sandbox0#808

Validation

• npm ci --ignore-scripts
• npm run typecheck
• npm test (716 passed)
• npm run lint
• npm run openapi:check (121 operations)
• npm run test:e2e -- --list (56 tests discovered)
• npm run build