Add Kimi K3 via OpenRouter

[brynary]

Summary

• add the opt-in OpenRouter catalog route moonshotai/kimi-k3
• mirror Kimi K3 context, output budget, reasoning controls, vision, prompt-cache pricing, and current token pricing
• add catalog snapshot coverage and a live-only catalog-backed deep tool round-trip test

No Kimi-specific production Rust is added; the route uses the existing OpenAI-compatible adapter.

Verification

• cargo nextest run --locked -p fabro-model -p fabro-llm (753 passed, 16 skipped)
• cargo +nightly-2026-04-14 clippy -p fabro-model -p fabro-llm --all-targets -- -D warnings
• cargo +nightly-2026-04-14 fmt --check --all
• live OpenRouter raw probe: required tool call, reasoning-token usage, and authoritative cost succeeded
• live Fabro deep probe: catalog-built OpenRouter client completed multiple Kimi K3 tool rounds with high reasoning effort and the correct final result

[Copilot]

Pull request overview

This PR extends the built-in model catalog to support the opt-in OpenRouter route moonshotai/kimi-k3, mirroring Kimi K3’s limits, feature flags (tools/vision/reasoning/prompt cache), reasoning controls, and pricing, and adds automated coverage to ensure the catalog entry is present and usable in live OpenRouter tool-round trips.

Changes:

• Added moonshotai/kimi-k3 to the OpenRouter built-in catalog with K3’s limits, features, controls, and costs.
• Added a catalog snapshot test to validate the built-in entry appears when OpenRouter is enabled and exposes the expected reasoning-effort controls.
• Added a live-only integration test that builds an OpenRouter client from the catalog and runs a deep tool round-trip against Kimi K3.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
lib/crates/fabro-model/src/catalog/providers/openrouter.toml	Adds the OpenRouter catalog row for moonshotai/kimi-k3 with limits/features/controls/costs.
lib/crates/fabro-model/src/catalog.rs	Adds a unit test + insta snapshot asserting Kimi K3 is present when OpenRouter is enabled and exposes expected controls.
lib/crates/fabro-llm/tests/integration.rs	Adds a live-only deep tool round-trip integration test using a catalog-built OpenRouter client for Kimi K3.

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