Compact CLAUDE.md and route development guidance

.claude/rules/development.md

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+---
+globs: ["src/**/*.py", "tests/**/*.py", "scripts/**/*.py", "pyproject.toml", "uv.lock", "maintain.sh", ".github/workflows/*.yml"]
+description: Command contracts, project gate, typing boundaries, and model-adjacent test invariants.
+---
+
+# Development invariants
+
+## Command contracts
+
+Every single-image command declares `source` with `dir_okay=False`; `batch` declares its directory with `file_okay=False`. Keep `tests/test_cli_robustness.py::TestDirectoryInputIsRejected` as the regression guard.
+
+Exit-code and no-signal behavior is a public contract. Read the command-line section of [`../../docs/module-internals.md`](../../docs/module-internals.md) before changing it.
+
+## Local gate
+
+Run `bash maintain.sh` from the repository root. The authoritative type gate is scoped to `src/`; full-project Pyright can exhaust Node memory on the ML dependency graph.
+
+Boundary modules for cv2, Torch, and Diffusers may carry narrow per-file relaxations for unknown third-party types. Keep pure-logic files strict, preserve the local piexif stub, and fix real errors before widening a pragma.
+
+## Model-adjacent tests
+
+Do not classify an entire module as untestable because its main path downloads a model. Keep pure behavior covered without downloads, including:
+
+- target-size selection in `test_invisible_engine.py`;
+- unsharp and adaptive-polish helpers in `test_humanizer.py`;
+- mocked device fallback in `test_img2img_runner.py`;
+- tiling geometry and blending in `test_tiling.py`.
+
+Use availability checks only for paths that actually load large models.
+
+Environment setup, dependency recovery, CI behavior, and fixture policy: [`../../docs/development.md`](../../docs/development.md).

docs/development.md

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+# Development
+
+Read this reference for environment setup, dependency recovery, CI behavior, and fixture policy. The always-loaded invariants remain in [`.claude/rules/development.md`](../.claude/rules/development.md).
+
+## Local environment
+
+- Use `uv sync --frozen --extra dev` and add only the feature extras needed for the task.
+- Do not use `uv pip install` for development tools. It can re-resolve `uv.lock` outside the compatible ML dependency set.
+- A core-only sync removes GPU packages by design. Package imports remain light through lazy exports; only removal paths should require the heavy stack.
+- On an unreliable connection, sync the needed `dev` and `gpu` extras and run the lint, type, and test commands directly instead of downloading every optional learned backend.
+- Run `uv` from the repository root or it may create a bare environment without the project dependencies.
+
+The optional TrustMark decoder downloads weights into its installed package directory. After pruning that extra, a leftover weights directory can make availability checks see an empty namespace package. If Pyright reports an unknown `TrustMark` import and `find_spec("trustmark")` returns a loader-less spec, remove that regenerable remnant from the active virtual environment and resync.
+
+## CI
+
+`.github/workflows/test.yml` runs Ruff and a cross-platform supported-Python test matrix with core plus development dependencies. GPU and model-running tests skip in that matrix; metadata, identification, visible removal, and the OpenCV eraser remain covered across operating systems.
+
+Keep `uv.lock` compatible with `uv sync --frozen`. Dependency pull-request checks use GitHub's merge result against current `main`; if `main` moves, merge it locally and rerun the full gate because a newer linter can expose stale directives in later code.
+
+Release and distribution behavior is canonical in [`release-and-distribution.md`](release-and-distribution.md).
+
+## Fixture and data policy
+
+[`../data/README.md`](../data/README.md) is the source of truth:
+
+- executable provenance fixtures live under `data/fixtures/`;
+- minimal controlled detector inputs live under `data/calibration/`;
+- canonical provider-oracle originals and their manifests live under `data/synthid/`;
+- evaluation-only ground truth lives under `data/evaluations/`;
+- runtime detector assets live in the package; unregistered research candidates remain outside the shipped wheel.
+
+Store each binary once. Point tests and manifests at its canonical path. Keep generated and cleaned outputs outside the repository and retain only reproducible public records allowed by the data policy.
+
+Use synthetic byte blobs for unsupported format paths and deterministic generated negatives where a real negative fixture is unnecessary. Detection and removal tests must preserve their format-specific invariants.