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/drizzle/0005_bent_violations.sql

@@ -0,0 +1 @@
+ALTER TABLE `servers` ADD `hide_proxmox_link` integer DEFAULT false NOT NULL;

server/drizzle/meta/_journal.json

@@ -36,6 +36,13 @@
       "when": 1789677988329,
       "tag": "0004_brown_gambit",
       "breakpoints": true
+    },
+    {
+      "idx": 5,
+      "version": "6",
+      "when": 1789759852933,
+      "tag": "0005_bent_violations",
+      "breakpoints": true
     }
   ]
 }