add-inference-component

# Add an Inference Component Runtime owns built-in processors and runners under `src/physicalai/inference/`; the manifest contract is described in `docs/reference/manifest-schema.md`. Keep this source-level workflow separate from configuring an exported policy with `pai-configure-inference`. ## Workflow 1. **Choose the component boundary.** Inspect `src/physicalai/inference/component_factory.py` and an existing preprocessor, postprocessor, or runner. Confirm whether the requested behavior belongs before or after the runner. - Done when: the input/output contract and manifest location are identified. 2. **Implement the component.** Subclass the matching Runtime base in `src/physicalai/inference/preprocessors/`, `postprocessors/`, or `runners/`. Resolve artifacts through the existing export-directory resolver; reject absolute and parent-traversal paths. - Done when: it works on representative tensors without depending on a robot or network service. 3. **Expose it to trusted manifests.** Register a short `type` with `ComponentRegistry` only when a stable built-in alias is useful. Otherwise require the existing `class_path` / `init_args` path. Keep nested specs under `_MAX_COMPONENT_DEPTH`. - Done when: `InferenceModel` can construct the component from a minimal local manifest. 4. **Test order and compatibility.** Extend `tests/unit/inference/preprocessors/`, `postprocessors/`, or `tests/unit/inference/test_model.py` (runners), plus `tests/unit/inference/test_manifest.py`, as appropriate. Check preprocessor → runner → postprocessor order and preserve old manifest behavior. - Done when: focused tests pass and one fake-observation inference returns the expected action shape. 5. **Document public additions** in `docs/reference/inference-api.md` or `docs/how-to/inference/configure-pre-post-processing.md`. - Done when: users can select the new type without reading source. ## Verify ```bash uv run pytest tests/unit/inference/preprocessors tests/unit/inference/postprocessors tests/unit/inference/test_model.py tests/unit/inference/test_manifest.py -q python3 .github/scripts/skills/agent_skills.py validate ```