Summary

• move headed reloadTestFile to an ack-style RPC so the host owns file completion tracking instead of keeping a long-lived birpc promise open for the full test run
• disable host/container birpc transport timeouts and close pending calls on WebSocket teardown so browser lifecycle timeouts stay under the host scheduler's control
• forward runId with headed file completion events and guard against stale completions during reruns and reconnects

Validation

• pnpm --filter @rstest/core build
• pnpm --filter @rstest/browser build
• pnpm --filter @rstest/browser-ui build
• pnpm --filter @rstest/browser typecheck
• pnpm --filter @rstest/browser-ui typecheck
• pnpm biome check 'packages/browser/src/hostController.ts' 'packages/browser-ui/src/hooks/useRpc.ts' 'packages/browser-ui/src/main.tsx' 'packages/browser-ui/src/types.ts'
• node 'packages/core/bin/rstest.js' run --browser.headless false 'tests/dom.test.ts' (cwd: e2e/browser-mode/fixtures/basic)
• node 'packages/core/bin/rstest.js' run --browser.headless false (cwd: e2e/browser-mode/fixtures/locator-api)
• node 'packages/core/bin/rstest.js' run --browser.headless false (cwd: e2e/browser-mode/fixtures/viewport)
• manual headed verification with a temporary 65s browser test to confirm reloadTestFile no longer fails at birpc's 60s default timeout