fix(service): reject encoded MCP paths

Reject percent signs in mcp_path so ASGI path decoding cannot turn an accepted configuration into an unreachable route. Cover encoded slash, space, and double-encoded slash inputs.

reme/components/service/http_service.py

@@ -205,7 +205,7 @@ class HttpService(BaseService):
             )
         if "//" in path or any(segment in {".", ".."} for segment in path.split("/")):
             raise ValueError("mcp_path must use non-empty literal path segments")
-        if any(char in path for char in "{}?#\\") or any(
+        if any(char in path for char in "{}?#%\\") or any(
             char.isspace() or ord(char) < 32 or ord(char) == 127 for char in path
         ):
             raise ValueError("mcp_path must be a literal URL path without route, query, or fragment syntax")

tests/unit/test_http_web_workspace.py

@@ -194,6 +194,9 @@ def test_http_service_rejects_invalid_or_conflicting_mcp_paths() -> None:
         "/{rest:path}",
         "/mcp?mode=test",
         "/mcp#fragment",
+        "/mcp%2Fv2",
+        "/mcp%20v2",
+        "/mcp%252Fv2",
         "/mcp path",
         "/mcp//nested",
         "/mcp/../nested",