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/examples/dynamicscript.js

@@ -0,0 +1,15 @@
+/**
+ * Module dependencies.
+ */
+
+var pug = require('../');
+
+var locals = {
+  users: {
+    tj: {age: 23, email: 'tj@vision-media.ca', isA: 'human'},
+    tobi: {age: 1, email: 'tobi@is-amazing.com', isA: 'ferret'},
+  },
+};
+
+var fn = pug.compileFile(__dirname + '/dynamicscript.pug');
+console.log(fn(locals));