fix(trial): resolve hosted control routes before execution

[stormstarlight]

Problem

Hosted Copilot trial is a custom provider catalog, but backend_uses_openai_catalog() still reports it as the personal OpenAI catalog. Automatic Manager classification, bounded DAG, /plan and rewrite routes can therefore resolve built-in catalog defaults instead of CLIENT_MODEL.

The later trial_model_options() CLI override does not make the earlier resolved model, admission/accounting metadata and validation consistent. This also conflicts with integrations that validate the model before spawning a worker.

Change

Exclude hosted trial from Copilot's personal catalog test, using the existing env/persisted trial resolver. The automatic control routes then reuse the existing role-level trial selector. Personal Copilot and Codex provider handling are unchanged. No saved model settings, gateway policy, or actual upstream model identity is changed or inferred.

Validation

• Added regressions for all four public control-route entry points and all automatic sentinels, with a deliberately non-built-in fixture selector.
• Covers persisted trial mode, no settings mutation, and unchanged personal-Copilot defaults.
• pytest tests/core/test_trial_control_routes.py tests/core/test_cheap_route_models.py tests/test_config_help.py: 76 passed on Windows/Python 3.11.
• Focused Ruff and git diff --check passed.
• This PR's tests do not use credentials, a model account or network access.

This is intentionally independent of draft #119. Windows plugin process/installation fixes are being kept in a separate dependent PR; no local preview UI redesign, cost-policy change, generated installer or credential is included here.