Make services canvas interactive

[arjunkomath]

Summary

• Add shared persisted service positions for the services canvas
• Replace the desktop services layout with draggable, snap-to-grid cards on a responsive scaled canvas
• Restyle service cards to match the deployment details card treatment, including attached volume sections and hover affordances

Verification

• pnpm exec biome check --write components/service/service-canvas.tsx db/schema.ts 'app/api/projects/[id]/services/[serviceId]/position/route.ts'
• pnpm exec tsc --noEmit --pretty false

Notes

• Requires running the normal Drizzle schema push so services get canvas_x and canvas_y columns.

[github-actions]

React Doctor found no new issues. 🎉

_{Reviewed by React Doctor for commit 312bde4.}