Add QUICKSTART.md

[jkleske]

Priority: P1

Problem

A developer who discovers this repo has no fast path to start using it. The current onboarding requires reading:

1. README.md (258 lines) — mostly methodology philosophy
2. CLAUDE.md (114 lines) — agent execution rules
3. PRD.md (355 lines) — template with all 10 lifecycle stages
4. MIGRATION.md — version migration notes

That's ~730 lines before writing a single line of product definition. There's no "clone, configure, go" path.

Proposed Change

Create QUICKSTART.md — a 5-step guide that gets a developer from fork to first gate in under 5 minutes:

# Quickstart

## 1. Fork & Clone
git clone <your-fork>
cd PRD-driven-context-engineering

## 2. Configure Your Domain
Edit `.claude/domain-profile.yaml`:
- Set `profile_type` (product, library, infrastructure, research)
- Customize `id_prefixes` if your domain uses different terminology

## 3. Initialize Your PRD
Open `PRD.md` and fill in the v0.1 Spark section:
- Problem Statement
- Desired Outcomes
- Success Signals
- Constraints

## 4. Start Building
Run `/prd-spark` (or the equivalent gate skill) to begin guided product development.
Claude will walk you through each sub-step.

## 5. Follow the Gates
Each PRD version (v0.1 → v1.0) has a gate checklist.
Run `./scripts/check-stage-gate.sh v0.2` to verify you're ready for the next stage.

Files to Change

File	Change
QUICKSTART.md	New file. 5-step quickstart as described above
README.md	Add link to QUICKSTART.md in a prominent position (e.g., first line after title)

Acceptance Criteria

• QUICKSTART.md exists at repo root
• Contains exactly 5 numbered steps
• Each step has a concrete action (command, file edit, or skill invocation)
• Total length ≤60 lines (concise, not comprehensive)
• References actual files in the repo (not hypothetical paths)
• References check-stage-gate.sh for gate verification
• README.md links to QUICKSTART.md
• No methodology philosophy — that's in README.md (or docs/METHODOLOGY.md per Separate methodology content from README working dashboard #53)

Verification

1. test -f QUICKSTART.md passes
2. A developer unfamiliar with the repo can follow all 5 steps without reading any other file
3. grep -l QUICKSTART README.md confirms the link exists

Related

• Issue Separate methodology content from README working dashboard #53 (README dashboard) — QUICKSTART link should be in the streamlined README