chore: add eclint for editorconfig linting and fix violations

- Install eclint ^2.8.1 for editorconfig validation and fixing
- Add .eclintignore to exclude generated files and dependencies
- Add npm scripts: lint:editorconfig and lint:editorconfig:fix
- Fix indentation issues in CONTRIBUTING.md (3 spaces -> 2 spaces)
- Fix code alignment in scanner.c to match editorconfig rules
- Regenerate parser after scanner.c formatting changes

.eclintignore

@@ -0,0 +1,21 @@
+# Dependencies
+node_modules/
+
+# Generated files
+src/parser.c
+src/grammar.json
+src/node-types.json
+src/tree_sitter/
+
+# Build artifacts
+build/
+dist/
+
+# Logs
+*.log
+megalinter-reports/
+
+# Lock files
+package-lock.json
+pnpm-lock.yaml
+yarn.lock