feat: add compose file discovery for scan mode

dockervault/discovery.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+COMPOSE_FILENAMES = (
+    "docker-compose.yml",
+    "docker-compose.yaml",
+    "compose.yml",
+    "compose.yaml",
+)
+
+
+def find_compose_files(root: str | Path) -> list[Path]:
+    root_path = Path(root).resolve()
+
+    if not root_path.exists():
+        raise FileNotFoundError(f"Scan root not found: {root_path}")
+
+    if not root_path.is_dir():
+        raise NotADirectoryError(f"Scan root is not a directory: {root_path}")
+
+    found: list[Path] = []
+
+    for path in root_path.rglob("*"):
+        if path.is_file() and path.name in COMPOSE_FILENAMES:
+            found.append(path)
+
+    return sorted(found)