fix: Conan 2 compliance for CI, packaging, and publishing workflow

[Copilot]

Conan 2 rejects exports_sources patterns starting with .., breaking conan export/conan create for this monorepo where thirdparty submodules live at ../../thirdparty relative to packages/tml-cpp/. Additionally, the package lacked a test_package/, the generated tml_export.h was never installed, and the CI had no Conan validation step.

conanfile.py

• Remove ../../thirdparty/rapidjson/* and ../../thirdparty/oniguruma/* from exports_sources (Conan 2 hard-rejects .. patterns via copy())
• Add export_sources() method to copy vendored submodules into the Conan cache using explicit absolute src paths — this is the correct Conan 2 escape hatch for monorepos
• Add smart THIRDPARTY_DIR resolution in generate(): use source_folder/thirdparty when present (cache build from conan create), fall back to ../../thirdparty (local conan install flow)
• Add package_type = "library"

CMakeLists.txt

• Introduce THIRDPARTY_DIR CMake variable (defaults to ../../thirdparty for bare CMake builds; Conan overrides via CMakeToolchain)
• Replace all hardcoded ../../thirdparty occurrences with ${THIRDPARTY_DIR}
• Install generated tml_export.h to include/tml/ — previously missing, breaking consumers who include c_api.h (which does #include "tml_export.h")

test_package/ (new)

Conan 2's conan create expects a test_package/ to verify the installed package end-to-end:

test_package/
  conanfile.py       # uses tested_reference_str + can_run() guard
  CMakeLists.txt     # find_package(TextMateLib) + links TextMateLib::tml
  src/example.cpp    # creates/disposes OnigLib and Registry via public C API

CI workflows

• build-and-test.yml: add conan-test job — installs Conan 2, detects profile, runs conan create packages/tml-cpp --build=missing from repo root (exercises export_sources() + test_package/)
• release.yml publish-conan: run conan create from repo root instead of packages/tml-cpp/; use Python to extract version from conanfile.py reliably; fix malformed regex character class in prior version-extraction script

[jbltx]

@copilot

home/runner/.conan2/p/b/textm15294e5504b89/p/lib/libtml.a(onigLib.cpp.o): in function `tml::DefaultOnigLib::~DefaultOnigLib()':
onigLib.cpp:(.text+0x17): undefined reference to `onig_end'
/usr/bin/ld: /home/runner/.conan2/p/b/textm15294e5504b89/p/lib/libtml.a(onigLib.cpp.o): in function `tml::OnigScanner::compilePatterns()':
onigLib.cpp:(.text+0x1bc): undefined reference to `OnigDefaultSyntax'
/usr/bin/ld: onigLib.cpp:(.text+0x1d3): undefined reference to `OnigEncodingUTF8'
/usr/bin/ld: onigLib.cpp:(.text+0x245): undefined reference to `onig_new'
/usr/bin/ld: onigLib.cpp:(.text+0x25c): undefined reference to `onig_error_code_to_str'
/usr/bin/ld: onigLib.cpp:(.text+0x303): undefined reference to `onig_regset_new'
/usr/bin/ld: /home/runner/.conan2/p/b/textm15294e5504b89/p/lib/libtml.a(onigLib.cpp.o): in function `tml::OnigScanner::dispose()':
onigLib.cpp:(.text+0x391): undefined reference to `onig_regset_free'
/usr/bin/ld: onigLib.cpp:(.text+0x3ea): undefined reference to `onig_free'
/usr/bin/ld: /home/runner/.conan2/p/b/textm15294e5504b89/p/lib/libtml.a(onigLib.cpp.o): in function `tml::OnigScanner::findNextMatchSync(tml::OnigString*, int, int)':
onigLib.cpp:(.text+0x7f5): undefined reference to `onig_regset_search'
/usr/bin/ld: onigLib.cpp:(.text+0x81b): undefined reference to `onig_region_new'
/usr/bin/ld: onigLib.cpp:(.text+0x83c): undefined reference to `onig_search'
/usr/bin/ld: onigLib.cpp:(.text+0x922): undefined reference to `onig_region_free'
/usr/bin/ld: onigLib.cpp:(.text+0x979): undefined reference to `onig_region_free'
/usr/bin/ld: /home/runner/.conan2/p/b/textm15294e5504b89/p/lib/libtml.a(onigLib.cpp.o): in function `tml::DefaultOnigLib::DefaultOnigLib()':
onigLib.cpp:(.text+0x4e3): undefined reference to `onig_init'
collect2: error: ld returned 1 exit status
gmake[2]: *** [CMakeFiles/example.dir/build.make:102: example] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:87: CMakeFiles/example.dir/all] Error 2
gmake: *** [Makefile:91: all] Error 2
ERROR: textmatelib/0.1.0 (test package): Error in build() method, line 20
	cmake.build()
	ConanException: Error 2 while executing

[Copilot]

@copilot

...

The linker failure was caused by two gaps in the Conan packaging:

1. cmake --install only installs libtml.a — Oniguruma is built via ExternalProject_Add and never ends up in the package.
2. package_info() only declared libs = ["tml"], so Conan's CMakeDeps generator didn't expose libonig.a to consumers at all.

Fixed in 66abc32:

• package() now copies libonig.a (and .lib on Windows) from build_folder/oniguruma/lib/ plus the Oniguruma headers (needed for installed onigLib.h which #include "oniguruma.h") into the Conan package.
• package_info() now declares cpp_info.libs = ["tml", "onig"] — order is intentional (tml references onig symbols, so tml must come first for static linkers).