chore: reorganize test files into domain-specific subdirectories under tests/

Split the monolithic test directory into three tiers (unit, api, e2e) with a path-mirroring directory structure. Added corresponding Makefile targets (test-unit, test-api, test-e2e) and updated all documentation references (CLAUDE.md, README.md, testing-cicd.html, testing-framework.html, testing-make.html) to reflect the new layout and naming conventions.

tests/e2e/devii/session.py

@@ -0,0 +1,22 @@
+# retoor <retoor@molodetz.nl>
+
+from tests.conftest import BASE_URL
+
+
+def test_devii_session_as_guest(page, app_server):
+    resp = page.request.get(f"{BASE_URL}/devii/session")
+    data = resp.json()
+    assert data["loggedIn"] is False
+    assert data["username"] == "guest"
+    assert "enabled" in data
+    assert "guestsEnabled" in data
+    assert data["baseUrl"] == BASE_URL
+
+
+def test_devii_session_as_logged_in(alice):
+    page, _ = alice
+    resp = page.request.get(f"{BASE_URL}/devii/session")
+    data = resp.json()
+    assert data["loggedIn"] is True
+    assert data["username"] == "alice_test"
+    assert "enabled" in data