Add ReDoS regression tests for 6 languages with zero current coverage (haskell, kotlin, lua, ruby, scala, swift) #1070

Issue

Six languages in tests/extraction/languages/ have literal zero ReDoS regression testing in their _strict.py files: haskell, kotlin, lua, ruby, scala, swift. Verified by grep -c for assert_redos_immune calls in each file.

This is a critical gap: an O(n²) backtracking bug in any of these languages' regex rules would go undetected. The shared test harness in tests/extraction/languages/_strict_harness.py provides the _best_of_timing method (geometric-growth payload scaling) which is the stronger ReDoS test than single-timeout checks.

Solution

For each of these 6 languages:

1. Add at least one _best_of_timing scaling-ratio test per language covering the most complex quantifier shapes in that language's regex rules (those most likely to exhibit O(n²) backtracking).
2. Prioritize rules with nested quantifiers, alternation with overlapping prefixes, or unbounded character classes (the recurring bug classes identified in epic Epic: Strict & exact regex test coverage for all structural signatures, per language #518).
3. Reference tests/extraction/languages/_strict_harness.py for the _best_of_timing(candidate_regex, pathological_case_list, ...) signature and existing usage in languages like c, cpp, csharp for examples.

Files to modify

• tests/extraction/languages/test_haskell_strict.py
• tests/extraction/languages/test_kotlin_strict.py
• tests/extraction/languages/test_lua_strict.py
• tests/extraction/languages/test_ruby_strict.py
• tests/extraction/languages/test_scala_strict.py
• tests/extraction/languages/test_swift_strict.py

Related issues

• Epic Epic: Harden the strict structural-signature test suite (non-extraction-pillar rules) per language #1069: Harden the strict structural-signature test suite (non-extraction-pillar rules) per language
• Epic Epic: Strict & exact regex test coverage for all structural signatures, per language #518: Strict & exact regex test coverage for all structural signatures, per language (CLOSED)
• Issue spec_exposure's unbounded [^\]]* ReDoS is copy-pasted across 28 languages, including already-merged yacc #713: spec_exposure's unbounded [^]]* ReDoS is copy-pasted across 28 languages