### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

Five Claude models that OpenRouter currently serves have no `openrouter/*` entry in `model_prices_and_context_window.json`, so litellm returns no pricing or token limits for them (cost tracking silently reports nothing; `get_model_info()` raises):

| Missing entry | OpenRouter live data (`GET /api/v1/models`) | |---|---| | `openrouter/anthropic/claude-sonnet-5` | ctx 1,000,000 / max out 128,000; $2/$10 per MTok | | `openrouter/anthropic/claude-opus-4.8` | ctx 1,000,000 / max out 128,000; $5/$25 per MTok | | `openrouter/anthropic/claude-opus-4.8-fast` | ctx 1,000,000 / max out 128,000; $10/$50 per MTok | | `openrouter/anthropic/claude-opus-4.7-fast` | ctx 1,000,000 / max out 128,000; $30/$150 per MTok | | `openrouter/anthropic/claude-fable-5` | ctx 1,000,000 / max out 128,000; $10/$50 per MTok |

These include the current Anthropic flagships (Claude Sonnet 5, Opus 4.8, Fable 5) — all of which already have first-party `anthropic` entries in the catalog; only the `openrouter/` routes are missing. Older OpenRouter Claude entries (opus-4.7, sonnet-4…