🔧 Add CI, nightly, and PR conventions

[Pililink]

Summary / 变更说明

• Add an adapted CI workflow for Avalon Atlas with Svelte/TypeScript checks, Rust backend tests, and a Windows portable package smoke test.
• Add a nightly workflow that builds a Windows portable prerelease from the current scheduled/manual ref or a future nightly branch.
• Expand the pull request template with gitmoji guidance, testing checklist, screenshots, and redaction reminders.
• Document commit conventions in CONTRIBUTING.md, while preserving the existing conventional commit style as acceptable.
• Expand issue contact links and fix one YAML quoting issue in the bug report template.

Related Issue / 关联 Issue

Closes #

Screenshots / 截图

Not applicable. Workflow and documentation changes only.

Testing / 验证

• YAML parsed successfully for workflows and issue templates using PyYAML.
• git diff --check
• npm run check
• GitHub Actions CI run 24972597359
  • Frontend Check
  • Rust Test
  • Windows Portable Smoke

Checklist / 自检

• The change is focused and does not include unrelated formatting churn.
• User-facing text is updated in both Chinese and English when applicable.
• Screenshots or notes are included for UI/OCR behavior changes.
• Logs, screenshots, and sample data are redacted before sharing.