Add SDLC definition kernel and skill adapters

[smota]

Summary

Implements first production slice for AgentFlow SDLC Definition Product v1.

Adds harness-neutral SDLC kernel, config/schema, state parser, validators, skill family, and generated skill adapter sync/status support.

Implemented issues

Implements #164
Implements #165
Implements #166
Implements #167
Implements #168
Refs #163

Related issues

Parent production epic: #163. Remaining implementation continues in #169, #170, #171, and #172.

Workflow evidence

Workflow-status comment: exception: this PR body records the role-pass summary for the first production slice; follow-up implementation issues remain open under #163.

Handover comments: exception: current session continues autonomous SDLC v1 implementation after this kernel PR.

Role-pass summary:

• Product/architecture: incorporated Claude/AGY/Codex packaging consult artifacts under .agent-runs/scratch/*packaging-response.md and the user direction that canonical product source must not live under harness-specific folders.
• Implementation: added docs/sdlc-definition.md, defaults/sdlc.config.json, SDLC schemas, lib/sdlc-state.mjs, lib/skill-adapters.mjs, validator scripts, and harness-neutral skills/sdlc-* packages.
• Validation: unit tests, direct validator execution, generated adapter dry-run, and fresh temp-repo install/sync/status smoke passed.

Validation evidence:

• pnpm test passed: 22 files / 144 tests.
• node scripts/validate-sdlc-config.mjs --json passed.
• node scripts/validate-sdlc-skill.mjs --path skills/sdlc-audit/SKILL.md --json passed.
• Fresh sandbox install produced docs/sdlc-definition.md, sdlc.config.json, schema, and SDLC skills.
• Fresh sandbox skills sync --harness all --apply generated Claude/Pi/.agents skill adapters and skills status reported 0 stale entries.

Agent review

• Implemented by: pi
• Launcher: pi
• Executor: pi-parent
• Transport: local-cli
• Delegation boundary: current-session
• Model / runtime: gpt-5.5 / pi
• Review: self-review
• Workflow profile: standard
• Merge owner: human/operator
• Mode: single-agent
• Self-review disclosure: Same session implemented and reviewed this first production slice; deterministic tests and sandbox smoke back the claim. Cross-harness consult was obtained before implementation.

CI-equivalent validation

• Status: passed
  Commands:
• pnpm prettier --write ...
• pnpm test
• node scripts/validate-sdlc-config.mjs --json
• node scripts/validate-sdlc-skill.mjs --path skills/sdlc-audit/SKILL.md --json
• Fresh temp repo: agentflow-sdlc init, sdlc validate, skills sync --harness all --apply, skills status --harness all --json

Follow-up issues

• Harness adapter projections #169 Harness adapter projections
• Migration and audit CLI product #170 Migration and audit CLI product
• Cockpit SDLC model alignment #171 Cockpit SDLC model alignment
• Fresh sandbox and release validation #172 Fresh sandbox and release validation

Out of scope

• Docker packaging.
• Publishing to npm in this slice.
• Full native plugin package formats for Claude/AGY/Codex/Pi; current slice adds generated skill adapters and lock/status base.