Let admins hide the Proxmox-link card per server

Not every registered server is a Proxmox VM/LXC -- bare-metal boxes
and other hosts had no reason to show a "link to Proxmox" option, but
it appeared unconditionally on every server's detail page.

New hideProxmoxLink column on servers (default false, so existing
behavior is unchanged until someone opts in). A "Not a VM? Hide this"
link in the card's header sets it; once hidden, a small "+ Show
Proxmox link options" link takes its place so it's still reachable,
not buried in a settings form. The card always shows regardless of
this flag once a server IS actually linked, so unlinking never becomes
unreachable by hiding the card out from under an active link.

Verified against a temp SQLite DB with real migrations: a new server
defaults to false, and toggling true/false both persist correctly.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

server/src/db/schema.ts

@@ -197,6 +197,13 @@ export const servers = sqliteTable("servers", {
   proxmoxNode: text("proxmox_node"),
   proxmoxGuestType: text("proxmox_guest_type").$type<ProxmoxGuestTypeCol>(),
   proxmoxVmid: integer("proxmox_vmid"),
+
+  // Not every server is a Proxmox guest (bare-metal boxes, other hosts) — an
+  // admin can hide the "Proxmox link" card on this server's detail page
+  // rather than seeing an irrelevant option on every server. Ignored (the
+  // card always shows) once a server IS actually linked, so unlinking stays
+  // reachable.
+  hideProxmoxLink: integer("hide_proxmox_link", { mode: "boolean" }).notNull().default(false),
 });
 
 export const scheduledTasks = sqliteTable("scheduled_tasks", {