#20404: test: isolate gateway auth env vars in test runner

## Summary - **Problem**: Tests fail when running locally with `OPENCLAW_GATEWAY_TOKEN` or `OPENCLAW_GATEWAY_PASSWORD` environment variables set. Specifically: - `src/browser/server.post-tabs-open-profile-unknown-returns-404.test.ts` - expects 400 but gets 401 - `src/gateway/server-runtime-config.test.ts` - expects rejection but gets resolved config with token - **Why it matters**: Developers who have gateway auth env vars set for local development cannot run tests successfully - **What changed**: Strip `OPENCLAW_GATEWAY_TOKEN` and `OPENCLAW_GATEWAY_PASSWORD` from the environment before spawning test processes in `scripts/test-parallel.mjs` - **What did NOT change**: Individual test files remain unchanged; this elevates the isolation pattern to the test runner level ## Change Type - [ ] Bug fix - [ ] Feature - [ ] Refactor - [ ] Docs - [ ] Security hardening - [x] Chore/infra ## Scope - [ ] Gateway / orchestration - [ ] Skills / tool execution - [ ] Auth / tokens - [ ] Memory / storage - [ ] Integrations - [ ] API / contracts - [ ] UI / DX - [x] CI/CD / infra ## Linked Issue/PR None ## User-visible / Behavior Changes None ## Security Impact - New permissions/capabilities? (`No`) - Secrets/tokens handling changed? (`No`) - New/changed network calls? (`No`) - Command/tool execution surface changed? (`No`) - Data access scope changed? (`No`) ## Repro + Verification ### Environment - OS: macOS / Linux - Runtime: Node.js 22+ ### Steps 1. Set gateway auth env vars: `export OPENCLAW_GATEWAY_TOKEN=test` 2. Run tests: `pnpm test -- --run src/gateway/server-runtime-config.test.ts` 3. Observe failures before fix, passes after fix ### Expected Tests should pass regardless of local environment variables ### Actual Tests fail when env vars are set ## Evidence - [x] Failing test/log before + passing after Before fix: ``` OPENCLAW_GATEWAY_TOKEN=test pnpm test -- --run src/gateway/server-runtime-config.test.ts # ❌ fails - expects rejection but resolves with token ``` After fix: ``` OPENCLAW_GATEWAY_TOKEN=test pnpm test -- --run src/gateway/server-runtime-config.test.ts # ✅ passes ``` ## Human Verification - Verified scenarios: Tests pass with env vars set, tests pass without env vars - Edge cases checked: Both `runOnce` and passthrough-args spawn paths - What was **not** verified: Windows environment (no access) ## Compatibility / Migration - Backward compatible? (`Yes`) - Config/env changes? (`No`) - Migration needed? (`No`) ## Failure Recovery - How to disable/revert: Revert commit `879a77498` - Known bad symptoms: None expected ## Risks and Mitigations None - this is a minimal test infrastructure fix with no production code changes.