Add a rights-aware coloring-book publication profile and line-art pipeline

[szmyty]

Outcome

Add a reusable Renderflow publication profile that can turn reviewed source material and approved illustrations into print-ready coloring books without making an external generator or unreviewed AI output canonical.

ColorBliss is an experience reference for prompt/photo-to-line-art, book assembly, consistent characters, and printable PDF output: https://colorbliss.com/. Study the workflow; do not copy its product, prompts, assets, or proprietary implementation.

Architecture

reviewed source + approved identity assets
        ↓
page and teaching-objective plan
        ↓
optional illustration/line-art provider adapters
        ↓
human review and rights/provenance gate
        ↓
deterministic Renderflow assembly
        ↓
print PDF + page assets + manifest + checksums

Renderflow owns the versioned transform graph, layout/profile contracts, deterministic assembly, validation, and publication derivatives. Creative providers remain optional adapters. Product repositories own their text, editorial approval, intended audience, and source artwork.

Scope

• Define a versioned coloring-book profile for page size, margins, bleed, safe area, line weight, complexity, audience, pagination, cover/back matter, and print metadata.
• Support reviewed source illustrations plus optional generated candidates that cannot advance without explicit approval and provenance.
• Preserve character/style continuity through stable reference identifiers and per-page constraints.
• Produce accessible text equivalents, captions, source links, licenses, approval status, and generated-artifact manifests.
• Emit print-ready PDF plus suitable per-page raster/vector derivatives when supported.
• Validate resolution, contrast, trim/bleed, blank-page intent, page ordering, duplicate pages, missing rights metadata, and unsupported fonts/assets.
• Provide a synthetic fixture and a small non-commercial sample book.

Acceptance criteria

• The profile has a versioned schema and deterministic build contract.
• Identical approved inputs produce byte-stable metadata and equivalent publication output.
• Every page traces to reviewed text/art sources and records rights/provenance.
• Generated images remain candidates until an explicit approval transition.
• Missing or ambiguous rights block public/commercial publication.
• Print geometry, resolution, pagination, and accessibility metadata are validated.
• The pipeline works without ColorBliss or another hosted provider.
• A provider can be replaced without changing canonical book source.
• Documentation covers authoring, review, local preview, build, print proofing, and rollback.

Non-goals

• Cloning ColorBliss.
• Scraping or redistributing third-party coloring pages.
• Automatically publishing or selling unreviewed books.
• Claiming that a generated page is suitable for a specific child or therapeutic use without review.

[szmyty]

First product canary

The first Ego Hygiene coloring-book publication is tracked separately in:

• https://github.com/egohygiene/egohygiene/issues/423

Renderflow owns the reusable profile/pipeline; the product repository owns editorial source, approved artwork, intended audience, rights decisions, and publication approval.