feat: add initial validatrix project with multi-language validator framework

Establish the Validatrix source code validation framework in Nim, including core detection, tokenization, and validation infrastructure for 10 languages (bash, HTML, JavaScript, Jinja, JSON, Nim, PHP, Python, TOML, YAML). The initial commit introduces the main validatrix.nim entry point with public API (validateSource, validateFile, inspectSource), a comprehensive test suite with per-language test files, build configuration via Makefile and .nimble, detailed LESSONS_LEARNED.md documenting 14 bug classes found during development, and a .gitignore excluding compiled binaries, logs, and build artifacts. The detector module provides extension-to-flavor mapping for 40+ file extensions and content-based language detection, while the debug module supports conditional compilation with -d:validatrixDebug for detailed tokenization logging.

.gitignore

@@ -0,0 +1,31 @@
+# Compiled binaries
+bin/
+*.out
+
+# Logs
+*.log
+
+# Python cache
+__pycache__/
+*.pyc
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# Build artifacts
+*.o
+*.obj
+*.a
+*.so
+
+# Test compiled binaries (source is .nim, binaries have no extension)
+tests/test_all
+tests/test_bash
+tests/test_nim
+tests/test_php
+
+# Editor files
+*.swp
+*.swo
+*~