fix(test): anchor Jest failure detection on the leading status marker

[houtinghang]

Summary

rtk test npm test labels a fully green suite [FAIL] FAILURES: as soon as any test name contains the substring FAIL (#3741). The Jest branch of extract_test_summary did line.contains("FAIL"), so a passing ✔ contains uppercase word FAIL in the name line was collected as a failure, while the same block's OUTPUT tail still showed ℹ fail 0.

This is the follow-up KuSh asked for in #3753 after #988 moved the runner into src/core/runner.rs ("anchoring the Jest match … would be welcome"). It takes the smaller of the two suggested routes: no new TestEcosystem variant, just an anchored match.

• Count a line as a failure only when its trimmed text starts with the runner's own status marker:
  • ✕ — Jest failed test
  • ✖ — node --test failed test (the reporter behind a bare npm test in the issue)
  • FAIL — Jest failed-suite header ( FAIL src/x.test.js after ANSI stripping, FAIL src/x.test.js without colour)
• Tests: / Test Suites: summary handling is unchanged.
• Regression tests next to the existing extract_test_summary tests: a green node --test run and a green Jest run whose test names contain FAIL stay green; a Jest FAIL header, a ✕ line and a node ✖ line are still reported, and the passing ✓ sibling is not quoted as a failure.

Closes #3741

Tests

• cargo fmt --all --check
• cargo clippy --all-targets
• cargo test (full suite). One integration test, unwritable_hooks_dir_never_breaks_the_hook, fails in my WSL environment with and without this change because the tests run as root there and root ignores the chmod the test relies on; unrelated to this PR.
• New tests fail on develop before the change and pass after it.
• End-to-end: the issue's two-file reproducer (node --test via npm test) through the built binary: rtk test npm test no longer prints [FAIL] FAILURES:.

AI disclosure

Written with the help of Claude (Anthropic); I reviewed the change and the test results above before opening this PR.

🤖 Generated with Claude Code

[rtk-wshm-sync-bot]

wshm · Automated triage by AI

📊 Automated PR Analysis

🐛 Type	bug-fix
🟢 Risk	low

Summary

Fixes a Jest/node --test failure-detection bug in src/core/runner.rs where any test name containing the substring "FAIL" was misclassified as a failure. The fix anchors failure detection to leading status markers (✕, ✖, or a "FAIL " suite header) instead of a bare substring match, and adds regression tests covering green and failing runs.

Review Checklist

• Tests present
• Breaking change
• Docs updated

Linked issues: #3741

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Analyzed automatically by wshm · This is an automated analysis, not a human review.