This refactors the existing integration tests into 3 priumary groups: fast,
release, and library. It also refines some of the release tests to drop some
of the older models and pick up newer models, while retaining the broad
coverage in the library group.
* test: integration test hardening
Improve reliability on slower systems, and some flakes. Fix
a few logic flaws on the newer tests, general hardening.
* tighten up vision logging
* add new models
* remove some older models - still covered by library scenarios
* integration: improve ability to test individual models
Add OLLAMA_TEST_MODEL env var to run integration tests against a
single model.
Enhance vision tests: multi-turn chat with cached image tokens, object
counting, spatial reasoning, detail recognition, scene understanding, OCR, and
multi-image comparison.
Add tool calling stress tests with complex agent-style prompts, large
system messages, and multi-turn tool response handling.
* review comments
