Fleet page: page through machines now that the API accepts a cursor (#156) #161

Epic: #119 · Depends on: #156 (merged)

Context

FM-910 (#150) requests listMachines({ limit: 200 }) once and shows "Showing the first N machines — the machines API cannot page further yet (#151)" when page.nextCursor is set. #156 added the cursor parameter, so the page can now fetch every machine.

Goal

apps/web/src/pages/fleet/useFleetInventory.ts fetches machines with the same fetchAllPages helper used for guests/tailnet devices (regenerate/verify the client type has cursor), keeping the 20-page safety cap and its per-source warning; remove the #151 banner text.

Acceptance criteria

• Multi-page machines load fully; the safety-cap warning appears only when the cap is hit
• Existing FleetPage tests updated (the single-request test becomes a multi-page test)
• pnpm lint/typecheck/test/build pass

Non-goals

• Other pages