feat: show swap usage in monitoring

[agentHits]

What is this PR about?

This PR adds optional swap usage visibility to the free Monitoring page's Memory Usage card. When swap data is available, the card now shows a second progress bar below the existing memory bar so users can see both RAM usage and swap usage at a glance.

The backend stores swap usage alongside the existing memory stats without changing the existing RAM fields, so older monitoring entries without swap data remain compatible. It uses node-os-utils swap data when available and falls back to sysctl -n vm.swapusage on macOS, where node-os-utils can report 0B / 0B even when macOS has active swap.

The UI only renders the Swap row when the reported swap total is greater than zero, keeping the current card unchanged on systems without swap.

Checklist

Before submitting this PR, please make sure that:

• You created a dedicated branch based on the canary branch.
• You have read the suggestions in the CONTRIBUTING.md file https://github.com/Dokploy/dokploy/blob/canary/CONTRIBUTING.md#pull-request
• You have tested this PR in your local instance. If you have not tested it yet, please do so before submitting. This helps avoid wasting maintainers' time reviewing code that has not been verified by you.

Testing

• corepack pnpm --dir apps/dokploy exec vitest --config __test__/vitest.config.ts __test__/monitoring/memory-swap.test.ts --run
• corepack pnpm exec biome check apps/dokploy/__test__/monitoring/memory-swap.test.ts apps/dokploy/components/dashboard/monitoring/free/container/show-free-container-monitoring.tsx apps/dokploy/components/dashboard/monitoring/free/container/docker-memory-chart.tsx packages/server/src/monitoring/utils.ts
• corepack pnpm --filter=server run typecheck
• corepack pnpm --filter=dokploy run typecheck
• git diff --check
• Tested locally at http://localhost:3000/dashboard/monitoring with swap displayed in the Memory Usage card.

Issues related (if applicable)

N/A

Screenshots (if applicable)