Follow-ups on top of #87210 (@liuhao1024) and #87246 (@JoaoMarcos44):
- resolve_startup_model_route: aggregator-native slugs stay on the current
routing aggregator (bare vendor slugs resolve WITHIN the aggregator first);
URL-bearing aliases resolve via direct_alias_runtime_request so a foreign
provider label never carries the vendor token to the alias host (#28660);
route carries the alias's own api_key.
- cli.py: pass current_provider; explicit --api-key wins over alias key.
- Drop #87246's oneshot double-handling (main's oneshot alias+detection path
already covers it once #87210's detection fix is in) and the PR-body SVG.
- Rewrote/extended startup-route tests for the hardened semantics.
33797073bb