Add initial note about FSD structure usage

[essaenko]

No description provided.

[airevieweragentapp]

🤖 AI Reviewer Report

Итог:
Adds a new file arch.md containing a single-line placeholder: "FSD structure will be used here later."

Оценка качества: 6 / 10

Найденные замечания:

• (low) arch.md:1 — The file contains only a single placeholder sentence and provides no structure, headings, or context.
  👉 Replace the placeholder with a meaningful outline or headings (e.g., purpose, intended audience, high-level structure) or, if the file is intentionally a placeholder, mark it explicitly as TODO and link to the tracking issue.
• (low) arch.md:1 — The acronym 'FSD' is used without being defined; readers may not know what it stands for.
  👉 Expand the acronym on first use (e.g., 'Feature-Specific Design (FSD)') or provide a brief definition.
• (low) arch.md:1 — As a markdown document, the file lacks common markdown structure (title, sections) which reduces discoverability and usefulness.
  👉 Add a top-level heading and section placeholders, and consider adding a short explanatory sentence about intended future content and owners.