fix(auth): auto-select provider flagship after login, not first catalog route

After a direct Anthropic/OpenAI login that supplies no activated model,
provider_model_to_select_after_auth fell back to matching_routes.first().
Live catalogs list claude-haiku-4-5 ahead of claude-opus-4-8, so an
Anthropic API-key login auto-selected Haiku instead of the flagship
default. When a provider has a curated flagship-first order
(ALL_CLAUDE_MODELS / ALL_OPENAI_MODELS), pick the highest-ranked matching
route; unranked providers (OpenAI-compatible, Copilot, ...) keep
live-catalog order. Model ids are normalized (lowercase, strip [1m] and
trailing -YYYYMMDD date) so dated catalog ids match canonical ids.

Adds regression tests covering the live Anthropic bug, Claude OAuth,
OpenAI, and unranked-provider catalog-order preservation.