feat: add optional RE2 regex engine support

[Copilot]

Adds an optional RE2 regex engine backend via a CCR_USE_RE2 CMake option.

• Introduces a RegexStrategy abstraction with StdRegexStrategy (std::regex) and Re2RegexStrategy (RE2) implementations; TreeRegexp now delegates to the strategy selected by RegexStrategyFactory, falling back to std::regex when RE2 is unavailable
• RE2 and abseil are fetched via CCR_FETCH_DEPS or auto-detected via find_package; sanitizer flags moved after external dependency fetching to avoid abseil/GCC ASan incompatibility
• CI matrix extended with -no-re2 presets to verify both code paths on all platforms
• README updated with CMake options reference and FetchContent usage example

[github-actions]

Test Results

27 tests  ±0   27 ✅ ±0   17s ⏱️ -10s
 1 suites ±0    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit 928f84e. ± Comparison against base commit f3c8f40.

♻️ This comment has been updated with latest results.

[github-actions]

✅⚠️MegaLinter analysis: Success with warnings

Descriptor	Linter	Files	Fixed	Errors	Warnings	Elapsed time
✅ ACTION	actionlint	6		0	0	0.03s
✅ CPP	clang-format	238	1	0	0	1.59s
✅ DOCKERFILE	hadolint	1		0	0	0.04s
⚠️ MARKDOWN	markdownlint	7	4	19	0	1.05s
✅ MARKDOWN	markdown-table-formatter	7	4	0	0	0.3s
✅ REPOSITORY	git_diff	yes		no	no	0.02s
✅ REPOSITORY	grype	yes		no	no	51.63s
✅ REPOSITORY	ls-lint	yes		no	no	0.1s
✅ REPOSITORY	secretlint	yes		no	no	4.45s
✅ REPOSITORY	syft	yes		no	no	1.69s
✅ REPOSITORY	trivy	yes		no	no	9.26s
✅ REPOSITORY	trivy-sbom	yes		no	no	0.19s
✅ REPOSITORY	trufflehog	yes		no	no	5.17s
⚠️ SPELL	lychee	86		2	0	3.15s
✅ YAML	prettier	10	0	0	0	0.67s
✅ YAML	v8r	10		0	0	8.58s
✅ YAML	yamllint	10		0	0	0.54s

Detailed Issues

⚠️ SPELL / lychee - 2 errors

[ERROR] https://www.contributor-covenant.org/version/2/0/code_of_conduct.html | Network error: error sending request for url (https://www.contributor-covenant.org/version/2/0/code_of_conduct.html) Maybe a certificate error?
[404] https://github.com/yourname/amp-cucumber-cpp-runner.git | Network error: Not Found
📝 Summary
---------------------
🔍 Total..........169
✅ Successful.....167
⏳ Timeouts.........0
🔀 Redirected.......0
👻 Excluded.........0
❓ Unknown..........0
🚫 Errors...........2

Errors in CODE_OF_CONDUCT.md
[ERROR] https://www.contributor-covenant.org/version/2/0/code_of_conduct.html | Network error: error sending request for url (https://www.contributor-covenant.org/version/2/0/code_of_conduct.html) Maybe a certificate error?

Errors in CONTRIBUTING.md
[404] https://github.com/yourname/amp-cucumber-cpp-runner.git | Network error: Not Found

⚠️ MARKDOWN / markdownlint - 19 errors

CHANGELOG.md:31 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Bug Fixes"]
CHANGELOG.md:37 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Chores"]
CHANGELOG.md:44 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Features"]
CHANGELOG.md:51 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Chores"]
CHANGELOG.md:59 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "⚠ BREAKING CHANGES"]
CHANGELOG.md:63 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Features"]
CHANGELOG.md:72 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Features"]
CHANGELOG.md:78 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Chores"]
CHANGELOG.md:86 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "⚠ BREAKING CHANGES"]
CHANGELOG.md:90 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Features"]
CHANGELOG.md:95 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Bug Fixes"]
CHANGELOG.md:104 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Features"]
CHANGELOG.md:115 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Chores"]
CHANGELOG.md:123 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "⚠ BREAKING CHANGES"]
CHANGELOG.md:127 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Features"]
CHANGELOG.md:152 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Bug Fixes"]
CHANGELOG.md:159 error MD024/no-duplicate-heading Multiple headings with the same content [Context: "Chores"]
cmake/WindowsToolchainFilesProvidedBy.md:1 error MD041/first-line-heading/first-line-h1 First line in a file should be a top-level heading [Context: "<https://github.com/MarkSchofi..."]
README.md:132 error MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]

See detailed reports in MegaLinter artifacts

Your project could benefit from a custom flavor, which would allow you to run only the linters you need, and thus improve runtime performances. (Skip this info by defining FLAVOR_SUGGESTIONS: false)

• Documentation: Custom Flavors
• Command: npx mega-linter-runner@9.4.0 --custom-flavor-setup --custom-flavor-linters ACTION_ACTIONLINT,CPP_CLANG_FORMAT,DOCKERFILE_HADOLINT,MARKDOWN_MARKDOWNLINT,MARKDOWN_MARKDOWN_TABLE_FORMATTER,REPOSITORY_GIT_DIFF,REPOSITORY_GRYPE,REPOSITORY_LS_LINT,REPOSITORY_SECRETLINT,REPOSITORY_SYFT,REPOSITORY_TRIVY,REPOSITORY_TRIVY_SBOM,REPOSITORY_TRUFFLEHOG,SPELL_LYCHEE,YAML_PRETTIER,YAML_YAMLLINT,YAML_V8R

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[Daan Timmer (daantimmer)]

Copilot resolve the cmake configure issues

[Copilot]

Copilot resolve the cmake configure issues

Fixed in d625ab2. The issue was that re2's install(EXPORT re2Targets ...) references abseil targets, but they weren't in any export set because ABSL_ENABLE_INSTALL was set to Off. Enabling it (same pattern as JSON_Install "On" for nlohmann_json) puts abseil targets in their own export set, which satisfies re2's install rules.

[Copilot]

Copilot there is now duplication in the matrix. I think we can get rid of the 'include' part and add an entry to the preset_suffix

Done — removed the include block and added "-no-re2" as an entry in preset_suffix: ["", "-no-re2"]. All 6 combinations (3 OS × 2 suffixes) are now generated from the single matrix definition without duplication.

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
87.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud