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-linker/test/index.test.js

@@ -0,0 +1,46 @@
+var assert = require('assert');
+var fs = require('fs');
+var link = require('../');
+
+function testDir(dir) {
+  fs.readdirSync(dir).forEach(function(name) {
+    if (!/\.input\.json$/.test(name)) return;
+    test(name, function() {
+      var actual = link(JSON.parse(fs.readFileSync(dir + '/' + name, 'utf8')));
+      expect(actual).toMatchSnapshot();
+    });
+  });
+}
+
+function testDirError(dir) {
+  fs.readdirSync(dir).forEach(function(name) {
+    if (!/\.input\.json$/.test(name)) return;
+    test(name, function() {
+      var input = JSON.parse(fs.readFileSync(dir + '/' + name, 'utf8'));
+      var err;
+      try {
+        link(input);
+      } catch (ex) {
+        err = {
+          msg: ex.msg,
+          code: ex.code,
+          line: ex.line,
+        };
+      }
+      if (!err) throw new Error('Expected error');
+      expect(err).toMatchSnapshot();
+    });
+  });
+}
+
+describe('cases from pug', function() {
+  testDir(__dirname + '/cases');
+});
+
+describe('special cases', function() {
+  testDir(__dirname + '/special-cases');
+});
+
+describe('error handling', function() {
+  testDirError(__dirname + '/errors');
+});