Add capstone project template pack for delivery, deployment, and incident-readiness practice

[Copilot]

This PR introduces a dedicated capstone template directory for realistic FDE project execution, covering discovery, architecture, implementation scaffolding, production launch readiness, enterprise troubleshooting, and post-incident learning. It also adds stakeholder-management scripts and scenario drills so readers can practice customer-facing delivery under real constraints.

• Template pack foundation

  • Added capstone-project-templates/README.md as the index for all new assets.
  • Added direct linkage from the portfolio/capstone section in README.md.

• Core capstone artifacts

  • Added customer-problem-statement-template.md with a filled sample customer brief.
  • Added architecture-diagram-template.md with a reusable Mermaid baseline and annotation checklist.
  • Added implementation-skeleton/ with backend/frontend/infra/runbook/docs templates.

• Customer execution under pressure

  • Added stakeholder-management-playbook.md with concrete scripts for:
    • scope-creep pushback
    • unrealistic production timeline negotiation
    • de-escalation and decision ownership

• Production go-live readiness

  • Added zero-to-one-production-checklist.md covering:
    • security hardening
    • environment variable and secret handling
    • smoke-test protocol and rollback readiness

• Enterprise environment operations

  • Added enterprise-troubleshooting-guide.md with structured playbooks for:
    • legacy database integration risk
    • missing/partial documentation recovery
    • restricted network access constraints

• Incident-to-product feedback loop

  • Added post-incident-review-templates.md including RCA structure that maps field failures into product/platform improvements.

• Practice scenarios

  • Added mock-customer-scenarios.md with curated briefs for architecture design and client presentation rehearsal.

capstone-project-templates/
├── customer-problem-statement-template.md
├── architecture-diagram-template.md
├── implementation-skeleton/
├── stakeholder-management-playbook.md
├── zero-to-one-production-checklist.md
├── enterprise-troubleshooting-guide.md
├── post-incident-review-templates.md
└── mock-customer-scenarios.md