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>

docs/90-harness-reference.md

@@ -90,7 +90,7 @@
 
 恢复步骤：
 
-1. 确认在仓库根目录（WSL 下为 `/mnt/d/OPC/skelet`）。
+1. 确认在仓库根目录（WSL 下为 `/mnt/d/opc_project/skelet`）。
 2. 读取 `AGENTS.md`、`docs/00-ai-start-here.md`、`docs/current-state.md`。
 3. 查看 `docs/06-tasks.md`，领取第一个 `TODO` 且依赖均为 `DONE` 的任务。
 4. 生产代码尚未初始化时先做 `T-001`，不要提前实现业务页面。