Document component prerequisites for manual installation

[Maya-Kid]

Why

Manual installation currently provides the target component's source without identifying the other components it imports. For example, copying Tool Steps into a fresh shadcn project fails because Diff View is missing.

What changes

Add visible manual prerequisites immediately before the installation tabs on Tool Steps, Turn Status, Composer, Context Ring and Panel. Each link leads to the required component's installation section and explicitly asks readers to follow its Manual instructions, including dependencies, first.

How it was checked

• Linux Node 24.13.0: fresh npm ci, docs generation, typecheck and production build passed against this commit's archived source. The five MDX file hashes match the local commit; registry output is unchanged.
• Chromium 145 at 1440 × 1000: checked all five pages in dark and light themes, clicked every prerequisite link, selected Manual, and copied each prerequisite and target source through the actual clipboard. The copied sources match the repository files.
• Five independent React 19.3 / Vite 8.3.4 consumers each received only its target and manually copied prerequisite components, plus packages named by their Manual pages. All strict TypeScript and production builds passed, as did step expansion, Turn Status disclosure, Composer submit/menu, Context Ring popover, and Panel row/close interactions. No shadcn add was used to fill these consumers.
• /dev/examples: 389/389 mounted, 0 failed in both themes, with no page errors. The existing composer-demo dynamic/static import build warning remains.

Before review

• Every commit is signed off (git commit -s)
• npm run typecheck and npm run build pass
• /dev/examples reports 0 failed
• What the change touches was looked at in both themes, open states included