refactor(artifacts): decouple artifact storage via repository pattern

[JWThewes]

WHY
The v2 framework hardcodes "markdown files in a directory tree" across skills, schemas, and every stage definition. Swapping the storage backend (e.g. to a graph database) would mean editing dozens of files. We want storage to be a single, swappable concern — change one adapter, not the methodology.

HOW
Introduce a port/adapter (repository) pattern:

• Port (conventions/repository-interface.md): a stable, backend-neutral contract. Artifacts are addressed by a logical TYPE token (e.g. requirements, components) — never a filename, extension, or path — plus a small set of named operations (saveArtifact, readArtifact, copyForwardArtifact, registerOutput, appendAuditEntry, verifyStage, ...).
• Adapter (src/repository//): the ONLY place that knows where and how artifacts are physically stored. Ships with the markdown-fs backend (adapter + paired verifier). A new backend = one adapter file + one verifier; nothing else changes.

Operations are a vocabulary of responsibilities, not an API. The adapter states the mechanism the agent uses to perform them: ordinary file tools for markdown-fs, or specific tools / an MCP server for other backends (e.g. a graph DB). The agent always reads the adapter to learn which.

WHAT

• Add port repository-interface.md (address model, type catalog, ops).
• Add repository/markdown-fs/ adapter (absorbs the old folder-structure.md
  • a type->representation map) and verifier.js (from process-checker.js, now resolving the new type/address state format).
• Add repository/README.md backend-authoring guide.
• Schemas: state outputs use {type, address} instead of {name, locationRelativeToIntentRoot}; reword workflow phase.
• Rewrite skills (work-method, stage-execution, orchestration, kickoff, workflow-composition) to speak the port vocabulary; remove "to disk" / "file system" / org-ai-kb leakage from backend-neutral steering.
• Strip extensions to type tokens across all 13 stage definitions and stage-graph.md.
• build.js: BACKEND selector wires the active adapter -> conventions/ and verifier -> tools/process-checker.js (Kiro hook path unchanged).
• Remove src/conventions/folder-structure.md and src/tools/process-checker.js (superseded by the adapter + paired verifier).

Methodology unchanged: stages, personas, state machine, autonomy, and review loops are untouched — only the storage vocabulary they speak through.

Summary

replace with your summary...

Changes

replace with a description of the changes

User experience

Please share what the user experience looks like before and after this change

Checklist

If your change doesn't seem to apply, please leave them unchecked.

• I have reviewed the contributing guidelines
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented

Test Plan

replace with instructions or a checklist for reviewers to verify

Acknowledgment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of the project license.