feat: mdgrep 0.1.0 – boolean full-text search for Markdown

- query language: substrings, phrases, /regex/, AND/OR/NOT (+ UND/ODER/NICHT),
  parentheses; case-insensitive; ReDoS protection via regex timeouts;
  syntax errors with stable code and position
- SearchEngine over in-memory blocks: filters, predicate, grouping, sorting,
  paging, time budget, automatic reload, highlighted snippets
- Markdown loader with split modes file/heading/list/paragraph
- grep-like CLI (mdgrep), JSON output, grep exit codes
- Flask blueprint/app with JSON API and widget assets, dev server
- framework-free JS widget: live search, URL state, filters, paging,
  syntax help, en/de labels, CSS custom properties for theming

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/site/index.html

@@ -0,0 +1,21 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width,initial-scale=1">
+  <title>mdgrep demo</title>
+  <link rel="stylesheet" href="api/mdgrep-static/mdgrep-widget.css">
+  <style>
+    body { font-family: system-ui, sans-serif; max-width: 48rem; margin: 2rem auto; padding: 0 1rem; }
+  </style>
+</head>
+<body>
+  <h1>mdgrep demo</h1>
+  <!-- Run: python -m mdgrep.web --dir examples/docs --split list --static examples/site -->
+  <div id="search"></div>
+  <script src="api/mdgrep-static/mdgrep-widget.js"></script>
+  <script>
+    MdGrep.mount(document.getElementById('search'), { endpoint: 'api/search', labels: 'en' });
+  </script>
+</body>
+</html>