fix(tests): auto-derive unique port+state-dir per worktree (fixes parallel pytest)

tests/_pytest_port.py

@@ -0,0 +1,42 @@
+"""
+Shared test server constants for use in individual test files.
+
+Instead of hardcoding ``BASE = "http://127.0.0.1:8788"`` in every test file,
+import from here so the port and state dir are always consistent with
+what conftest.py computed for this worktree.
+
+Usage::
+
+    from tests._pytest_port import BASE
+
+conftest.py publishes ``HERMES_WEBUI_TEST_PORT`` and
+``HERMES_WEBUI_TEST_STATE_DIR`` to ``os.environ`` at module level
+(before any test file is imported), so this module always reads the
+correct values.  The auto-derivation fallback matches conftest's logic
+exactly, so standalone imports also work correctly.
+"""
+import hashlib
+import os
+import pathlib
+
+def _auto_test_port(repo_root: pathlib.Path) -> int:
+    h = int(hashlib.md5(str(repo_root).encode()).hexdigest(), 16)
+    return 20000 + (h % 10000)
+
+def _auto_state_dir_name(repo_root: pathlib.Path) -> str:
+    h = hashlib.md5(str(repo_root).encode()).hexdigest()[:8]
+    return f"webui-test-{h}"
+
+_TESTS_DIR   = pathlib.Path(__file__).parent.resolve()
+_REPO_ROOT   = _TESTS_DIR.parent.resolve()
+_HERMES_HOME = pathlib.Path(os.getenv('HERMES_HOME',
+                             str(pathlib.Path.home() / '.hermes')))
+
+TEST_PORT = int(os.environ.get('HERMES_WEBUI_TEST_PORT',
+                               str(_auto_test_port(_REPO_ROOT))))
+BASE = f"http://127.0.0.1:{TEST_PORT}"
+
+TEST_STATE_DIR = pathlib.Path(os.environ.get(
+    'HERMES_WEBUI_TEST_STATE_DIR',
+    str(_HERMES_HOME / _auto_state_dir_name(_REPO_ROOT))
+))