docs(product): sync cody-engine direction from seed deck v0.3

[thxforall]

Context

Sources:

• Local deck: /Users/kiyeol/Downloads/decoded-deck (1).pdf (decoded. 코디 재현 엔진 · AI 스타일 커머스, Seed Pitch v0.3, 2026-05-27)
• Supplemental shared conversation: https://chatgpt.com/share/6a1472ff-d7a8-83a5-862e-448d909a56ab
• Repo routing: AGENTS.md, docs/agent/README.md, and docs/wiki/schema/ownership-matrix.md
• Existing local pointer: .planning/cody-stage1-eval.md links to decoded-docs Architecture/cody-engine.md, ADR-0005, Project/open-questions.md, and sprint docs.

Problem

The deck sharpens the current product direction around a consumer cody reproduction engine, but the durable docs and monorepo pointers need to be aligned without turning this monorepo into a second product-strategy SSOT.

Product canon to capture at the right layer:

• Input: Instagram/Pinterest screenshot, direct photo, or URL.
• Pipeline: upload -> VLM decomposition -> style formula -> catalog matching -> recommended look sets.
• Core IP: must_keep vs replaceable style formula; decoded preserves the look, not necessarily the exact original item.
• Phase 1 surface: Upload, Analysis, Conditions, Recommended Looks, Item Detail, plus Shop this look slug pages.
• Phase 1 conditions are not optional later work: budget, mall, fit, and gender defaults belong in the launch flow.
• Explicit exclusions for this doc pass: VTON, native checkout/payment, public feed, and broad expansion surfaces.
• Business-model boundary: affiliate-first redirect; decoded does not own checkout, returns, or inventory in this phase.

Scope

• Update decoded-docs canonical docs first: product brief/project overview, Architecture/cody-engine.md, relevant open questions, and ADR pointers if needed.
• Update monorepo pointer docs only where stale: likely docs/agent/architecture-summary.md, docs/agent/web-routes-and-features.md, docs/agent/README.md, or related agent inventory pointers.
• Preserve or correct .planning/cody-stage1-eval.md cross-links if vault paths changed.
• Split implementation gaps into separate issues instead of bundling them into this docs issue.

Grill-docs question

Question: should the durable term be decoded cody engine, cody-engine, or style reproduction engine?

Recommended answer: use cody-engine internally for architecture/tasks and 코디 재현 엔진 or style reproduction engine externally. Avoid renaming the product away from decoded.

Acceptance criteria

• Canonical vault docs capture the deck v0.3 product scope, pipeline, core IP, launch boundaries, and explicit exclusions.
• Monorepo docs remain concise pointers/summaries and do not become a second product-strategy SSOT.
• Agent-facing docs tell future agents where to read cody-engine architecture and product scope before implementation.
• Any code implementation gaps discovered during the docs update are split into separate issues.

Out of scope

• Implementing the pipeline.
• Editing generated API clients.
• Moving harness wiki content to the vault.
• Treating VTON/public feed/native checkout as Phase 1 work.