Repo hygiene: fix .gitignore, normalize line endings, correct repo paths

- Replace misspelled/ineffective ignore file with a real .gitignore:
  deploy/ (contains SSH private key), *.pem, .env*, and Python/Django/
  Wagtail runtime artifacts are now excluded from version control
- Add .gitattributes (* text=auto eol=lf) to stop CRLF/LF churn that
  made all 26 tracked files show spurious full-file diffs
- Correct repo root path /mnt/d/OPC/skelet -> /mnt/d/opc_project/skelet
  in AGENTS.md, 00-ai-start-here, 03-tech-stack, 90-harness-reference,
  current-state (progress.md history left as-is, append-only)
- Update current-state.md snapshot and append maintenance record to
  progress.md per harness rules

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,23 @@
+# 部署凭证与私有环境信息，绝不提交（含 SSH 私钥）
+deploy/
+*.pem
+.env
+.env.*
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+
+# Django / Wagtail
+db.sqlite3
+db.sqlite3-journal
+db.sqlite3-wal
+db.sqlite3-shm
+media/
+staticfiles/
+
+# 系统与编辑器
+.DS_Store
+Thumbs.db