[FEATURE] Secret Schema & Validation

[mors119]

Why

Projects often require secrets without documenting them.

New contributors have no idea

• what is required
• what is optional
• what each secret is used for

---

Schema

DATABASE_URL:
  description: PostgreSQL connection
  required: true

OPENAI_API_KEY:
  description: AI integration
  required: false

---

CLI

flvt secret doctor

Output

✓ DATABASE_URL

✓ JWT_SECRET

✗ OPENAI_API_KEY missing

---

Acceptance Criteria

• schema parser
• required validation
• optional validation
• human-readable diagnostics