[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>

docs/CLAUDE.md

@@ -74,7 +74,7 @@ SOLUTION_ERP/
 │   └── changelog/
 │       ├── migration-todos.md      Roadmap 5 phase
 │       └── sessions/               YYYY-MM-DD session logs
-├── .claude/skills/                 Skill library (contract-workflow, form-engine, ...)
+├── .claude/skills/                 6 skill: 3 domain (contract-workflow, form-engine, permission-matrix) + 3 ops (dependency-audit-erp, ef-core-migration, iis-deploy-runbook)
 ├── scripts/                        parse_forms.py, parse_workflow.py, seed, deploy
 ├── SolutionErp.slnx                Solution file
 ├── global.json                     .NET 10 SDK pin