Name routes after node id, not component

Using `node.id` would produce route names like `r_transmon_1_transmon_2` instead of `r_transmon_transmon$N`. The advantage is that the route name would directly identify which specific node pair it connects, not just which component types. This would be more informative for debugging.

Technically, any change to auto-generated names can be breaking if downstream code depends on specific name patterns (e.g., string matching on GDS cell names). In practice:
- `uniquename()` already appends a counter suffix (`$N`), so names are not stable across sessions anyway.
- The docstring says `name` should be unique but does not specify the format.
- Users can always pass `name=...` explicitly to override.

Start by locating the route auto-naming entry point and inspect how node.id and uniquename() contribute to generated names. Check the name docstring and existing handling of explicit name= overrides; done means generated names identify the specific node pair while preserving explicit names.

Written by the indexing model from the issue text.