test(e2e): wire EuRoC CI-tier test with skip-when-absent fixture

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/e2e/conftest.py

@@ -0,0 +1,36 @@
+"""Shared fixtures for e2e tests — dataset discovery + skip markers."""
+
+from pathlib import Path
+
+import pytest
+
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+DATASETS_ROOT = REPO_ROOT / "datasets"
+
+
+@pytest.fixture(scope="session")
+def euroc_mh01_root() -> Path:
+    root = DATASETS_ROOT / "euroc" / "MH_01"
+    if not (root / "mav0").is_dir():
+        pytest.skip(
+            f"EuRoC MH_01 not present at {root}. "
+            "Run `python scripts/download_dataset.py euroc_mh01` to fetch it."
+        )
+    return root
+
+
+@pytest.fixture(scope="session")
+def vpair_sample_root() -> Path:
+    root = DATASETS_ROOT / "vpair" / "sample"
+    if not root.is_dir():
+        pytest.skip(f"VPAIR sample not present at {root}.")
+    return root
+
+
+@pytest.fixture(scope="session")
+def mars_lvig_root() -> Path:
+    root = DATASETS_ROOT / "mars_lvig"
+    if not root.is_dir():
+        pytest.skip(f"MARS-LVIG not present at {root}.")
+    return root