Align runtime behavior with test and stream expectations across the app.
Use `globalThis` timer APIs for SSE heartbeats, set the Playwright
server `NODE_ENV` explicitly by mode, and fall back to Codex pricing
lookups after stripping effort suffixes when a direct model match is
missing.
Refresh affected unit and e2e coverage to use deterministic timers and
updated settings navigation so timeout- and stream-related assertions are
stable on release builds.
7b80e80a1e