feat: markdown API documentation rendering

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_markdown.py

@@ -0,0 +1,31 @@
+from auto_reverse.doc.markdown import render_markdown
+from auto_reverse.models import EndpointRecord, Signature
+
+
+def _rec(method, template, **kw):
+    rec = EndpointRecord(signature=Signature(method, "ex.com", template, "2xx"))
+    for k, v in kw.items():
+        setattr(rec, k, v)
+    return rec
+
+
+def test_renders_heading_and_endpoints():
+    md = render_markdown([_rec("GET", "/api/users", summary="List users")], title="ex.com API")
+    assert "# ex.com API" in md
+    assert "`GET /api/users`" in md
+    assert "List users" in md
+
+
+def test_groups_by_tag():
+    records = [
+        _rec("GET", "/api/users", tag="Users"),
+        _rec("GET", "/api/cart", tag="Cart"),
+    ]
+    md = render_markdown(records, title="x")
+    assert "## Users" in md
+    assert "## Cart" in md
+
+
+def test_untagged_go_under_general():
+    md = render_markdown([_rec("GET", "/api/x")], title="x")
+    assert "## General" in md