[CLAUDE] Skill: thêm 3 skill ops project-specific

Khảo sát alirezarezvani/claude-skills repo — phần lớn skill đã có ở
user-level (code-reviewer, sql-database-assistant, focused-fix,
senior-frontend, mcp-builder...). Bulk import sẽ trùng + nhiều skill
là doc-dump generic không có YAML when-to-use.

Thay vào đó: viết 3 skill PROJECT-SPECIFIC encode kiến thức
SOLUTION_ERP-only mà generic không thể biết:

- dependency-audit-erp: dotnet list --vulnerable + npm audit cho
  fe-admin/fe-user, respect pin constraint MediatR 12.4.1 +
  Swashbuckle 6.9.0 + Node 20.x, dẫn chiếu gotchas, output template
  + CI integration TODO Phase 5.1

- ef-core-migration: 8 migration history + 3-file rule + Design
  TimeDbContextFactory + 6 pitfalls cụ thể (bao gồm cascade vs
  restrict cho WorkflowDefinitionId), workflow add entity mới end-
  to-end, prod apply via idempotent script

- iis-deploy-runbook: 3 IIS site topology + win-acme cert + NSSM
  gitea-runner shared VIETREPORT + LibreOffice 25.8.6 headless,
  debug playbook 500/502/SignalR/login, deploy steps + manual
  emergency, rotate creds + backup commands, dẫn chiếu gotcha #25/26/28/29

Skills README cập nhật: 6 skill (3 domain + 3 ops). CLAUDE.md
+ docs/CLAUDE.md sync count.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -75,7 +75,7 @@ Kiến trúc: **.NET 10 Clean Architecture + 2 React FE (admin + user) + SQL Ser
 | [`docs/database/schema-diagram.md`](docs/database/schema-diagram.md) | ⭐ ERD + luồng DB + data flow 19 table |
 | [`docs/flows/README.md`](docs/flows/README.md) | Index 6 flow (auth, permission, contract, form, SLA) |
 | [`docs/gotchas.md`](docs/gotchas.md) | ⭐ 26 bẫy đã gặp — đọc trước khi debug tương tự |
-| [`.claude/skills/`](.claude/skills/README.md) | 3 skill: contract-workflow, form-engine, permission-matrix |
+| [`.claude/skills/`](.claude/skills/README.md) | 6 skill: contract-workflow, form-engine, permission-matrix, dependency-audit-erp, ef-core-migration, iis-deploy-runbook |
 | [`docs/guides/vps-setup.md`](docs/guides/vps-setup.md) | ⭐ Master runbook deploy VPS shared với VIETREPORT |
 
 ## ⚠️ Kết thúc session