fix: add scoped error logging for lexer/parser errors

- Add std.log.scoped(.pugz) to template.zig and view_engine.zig
- Log detailed error info (code, line, column, message) when parsing fails
- Log template path context in ViewEngine on parse errors
- Remove debug print from lexer, use proper scoped logging instead
- Move benchmarks, docs, examples, playground, tests out of src/ to project root
- Update build.zig and documentation paths accordingly
- Bump version to 0.3.1

tests/sample_data/pug-load/test/index.test.js

@@ -0,0 +1,30 @@
+'use strict';
+
+var fs = require('fs');
+var path = require('path');
+var assert = require('assert');
+var walk = require('pug-walk');
+var lex = require('pug-lexer');
+var parse = require('pug-parser');
+var load = require('../');
+
+test('pug-load', () => {
+  var filename = __dirname + '/foo.pug';
+  var ast = load.file(filename, {
+    lex: lex,
+    parse: parse,
+  });
+
+  ast = walk(
+    ast,
+    function(node) {
+      if (node.filename)
+        node.filename = '<dirname>/' + path.basename(node.filename);
+      if (node.fullPath)
+        node.fullPath = '<dirname>/' + path.basename(node.fullPath);
+    },
+    {includeDependencies: true}
+  );
+
+  expect(ast).toMatchSnapshot();
+});