Slim fixture: mic-clip-slim

A 3.5M-parameter fixture for the clip MIC, covering openai/clip-vit-base-patch32. It is a test artifact, not a usable model, tagged test-artifact to keep it out of candidate-model search.

• Fixture key b50917f048e5. It covers every checkpoint whose processor files are byte-identical and whose config matches after shrinking.
• Same architecture, smaller config: CLIPModel, shrunk by the generic rule in sweep.py (text num_hidden_layers 2, vision num_hidden_layers 2).
• Processor files copied byte for byte from openai/clip-vit-base-patch32: merges.txt, preprocessor_config.json, special_tokens_map.json, tokenizer.json, tokenizer_config.json, vocab.json.
• Random weights (seed 17). They passed the input-sensitivity gate: every perturbation of the contract's inputs moved the logits by at least 0.001 (weakest: pixel_values:halve, 0.00487), so no training was needed.
• Same tensor names as the real checkpoint. The real checkpoint has every parameter, and so does the fixture.
• Saved in float32, the dtype openai/clip-vit-base-patch32 loads in by default.
• Finite in float32, bfloat16, and float16 (forward, loss, gradients).

Built by build_fixtures.py; build.json records the pinned sources, gate results, and file hashes. The source repository commits only README.md and build.json; rebuild the other files with python example/build_fixtures.py --fixture mic-clip-slim.