Motivation

• Remove fragile/race-prone gateway behavior and hardcoded endpoints in the Web UI so environments and first-call flows behave predictably.
• Reduce CI/local e2e brittleness caused by a hardcoded base URL and repository-tracked screenshot artifacts.
• Reflect remediation progress in the branch audit by documenting remaining issues and what was addressed.

Description

• Make the gateway endpoint configurable by reading import.meta.env.VITE_GATEWAY_URL with a ws://localhost:18789 fallback, replacing the previous hardcoded value in useGateway.
• Add a connection promise/handshake mechanism to useGateway so call() awaits a successful hello handshake instead of rejecting immediately, and track/resolve/reject that promise across open/error/close/timeout flows.
• Change hello timeout behavior to set an explicit error state, reject waiting callers, and close the socket instead of treating the connection as connected on timeout.
• Update Playwright smoke tests to read PLAYWRIGHT_BASE_URL (fallback http://127.0.0.1:5173) and to write screenshots to ephemeral artifact paths with testInfo.outputPath(...) rather than writing tracked files.
• Add apps/web-next/screenshots/ to .gitignore and remove previously committed screenshot binaries to avoid repository churn.
• Replace docs/branch-upstream-audit.md with a focused document that lists remaining unresolved issues and records the specific fixes applied in this pass.

Testing

• Ran repository validation with git diff --check, which reported no whitespace/check issues.
• Attempted a local build with pnpm -C apps/web-next build; the build failed in this environment due to missing node_modules and missing React/type dependencies, not because of the code changes (build failure is an environment dependency issue).
• No CI Playwright run was performed in this environment; e2e test files were updated to be CI/config-friendly and to emit artifacts to Playwright output paths.

Codex Task