fix: price qualified shell models on their selected service

[ZeroPoint95]

• Fix shell program budget estimates for connection-qualified model names and thinking-level suffixes, using the same selected service and bare model id as the provider adapter.
• Keep unknown and unpublished prices conservative, and prevent direct services from borrowing OpenRouter tariffs for matching ids.
• Document the pricing behavior and cover concurrent admission, recorded settlement, held calls and oversized-call refusal.

Validation: failing-before/passing-after offline regressions; focused race checks and existing model API budget controls; make build; exact-base make pr-ready; independent review. No live provider experiment performed for this repair.

Release acceptance remains incomplete: the preceding live review trial failed to assemble a review, and the corrected pricing candidate has not had a live retry. This PR is ready for source review; it does not establish completed release acceptance.