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/test/examples.test.js

@@ -0,0 +1,23 @@
+'use strict';
+
+var fs = require('fs');
+var pug = require('../');
+
+describe('examples', function() {
+  fs.readdirSync(__dirname + '/../examples').forEach(function(example) {
+    if (/\.js$/.test(example)) {
+      it(example + ' does not throw any error', function() {
+        var log = console.log;
+        var err = console.error;
+        console.log = function() {};
+        console.error = function() {};
+        try {
+          require('../examples/' + example);
+        } finally {
+          console.log = log;
+          console.error = err;
+        }
+      });
+    }
+  });
+});