feat(paths): abstract runtime path logic for frozen distribution packages (#969)

* feat(core): abstract runtime path logic for frozen distribution packages

* Address review feedback: revert browser MCP check, persistent data dir default when frozen, and add path tests

tests/test_runtime_paths.py

@@ -0,0 +1,50 @@
+import os
+import sys
+from unittest import mock
+import pytest
+from src.runtime_paths import get_app_root, get_default_data_dir
+
+
+def test_get_app_root_normal_run():
+    """Verify that get_app_root returns the repository root parent of src/ when not frozen."""
+    with mock.patch.object(sys, "frozen", False, create=True):
+        app_root = get_app_root()
+        # Verify it is a valid directory path and matches expected parent structure
+        assert os.path.isdir(app_root)
+        assert os.path.exists(os.path.join(app_root, "src"))
+
+
+def test_get_app_root_frozen_with_meipass():
+    """Verify that get_app_root returns the sys._MEIPASS directory when frozen by PyInstaller."""
+    mock_meipass = os.path.abspath("mock_meipass_dir")
+    with mock.patch.object(sys, "frozen", True, create=True), \
+         mock.patch.object(sys, "_MEIPASS", mock_meipass, create=True):
+        app_root = get_app_root()
+        assert app_root == mock_meipass
+
+
+def test_get_app_root_frozen_without_meipass():
+    """Verify that get_app_root falls back to the sys.executable parent directory when frozen but _MEIPASS is absent."""
+    mock_exe_path = os.path.join(os.path.abspath("mock_exe_dir"), "Odysseus.exe")
+    with mock.patch.object(sys, "frozen", True, create=True), \
+         mock.patch.object(sys, "executable", mock_exe_path, create=True):
+        # Remove sys._MEIPASS if it exists in the test process environment
+        if hasattr(sys, "_MEIPASS"):
+            delattr(sys, "_MEIPASS")
+        app_root = get_app_root()
+        assert app_root == os.path.abspath("mock_exe_dir")
+
+
+def test_get_default_data_dir_normal():
+    """Verify that get_default_data_dir resolves to get_app_root() / 'data' when not frozen."""
+    with mock.patch.object(sys, "frozen", False, create=True):
+        res = get_default_data_dir()
+        assert res == os.path.join(get_app_root(), "data")
+
+
+def test_get_default_data_dir_frozen():
+    """Verify that get_default_data_dir resolves to a persistent user path under ~ when frozen."""
+    with mock.patch.object(sys, "frozen", True, create=True):
+        res = get_default_data_dir()
+        expected = os.path.join(os.path.expanduser("~"), ".odysseus", "data")
+        assert res == expected