Add per-server admin-page links (Dockge, Webmin, Cockpit, etc.)

Each server's detail page gets an "Admin Links" card for bookmarking
that host's own web UIs -- container managers, Webmin, Cockpit, or
anything else reachable by URL -- so there's a quick way to jump
there without hunting down the address each time.

New server_links table (serverId FK, label, url, ON DELETE CASCADE so
removing a server cleans up its links automatically) and three new
routes: POST/PATCH/DELETE /api/servers/:id/links, gated to operator+
like the rest of this page's editing actions; the existing GET
/:id/detail now includes the server's links alongside hardware/DNS
info. URLs are validated to start with http:// or https:// server-side
(rejecting e.g. a javascript: URL that would otherwise render as a
clickable link).

Rendered as a row of pill buttons (label opens the URL in a new tab),
with inline edit/remove controls next to each when the viewer can
edit, and an "Add link" form matching the existing task-form style on
the same page.

Verified against a temp SQLite DB with real migrations: create/list/
update/delete all work, and deleting the parent server cascades to
remove its links rather than leaving them orphaned.

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

server/src/db/schema.ts

@@ -222,6 +222,20 @@ export const scheduledTasks = sqliteTable("scheduled_tasks", {
     .default(sql`(current_timestamp)`),
 });
 
+// ─── Server links — admin-page bookmarks per server (Dockge, Webmin, Cockpit, etc.) ─
+
+export const serverLinks = sqliteTable("server_links", {
+  id: integer("id").primaryKey({ autoIncrement: true }),
+  serverId: integer("server_id")
+    .notNull()
+    .references(() => servers.id, { onDelete: "cascade" }),
+  label: text("label").notNull(),
+  url: text("url").notNull(),
+  createdAt: text("created_at")
+    .notNull()
+    .default(sql`(current_timestamp)`),
+});
+
 // ─── Live integrations (Proxmox, Synology, Semaphore, Tailscale, Gitea, Dockhand) ─
 
 export const integrationTypes = [