Graceful degradation before partnership/SSH is set up

Fix 1 — Monitor partner card (common.php + monitor.php):
  vv_remote_hosts_stats() no longer skips hosts with no API key.
  Returns no_api_key:true entry instead. Monitor JS renders
  "API key not configured — complete Onboard to enable" instead
  of a blank space.

Fix 2 — rawconf push not alarming pre-onboard (config.php + scheduler.php):
  Probe failures (Tailscale not found, plugin not installed) now carry
  ready:false. JS treats ready:false results silently — button shows
  "✓ Saved" not "push failed: HOST2" before SSH is set up.
  Only genuine post-onboard failures (ready not false) show as errors.

Fix 3 — Partnership Onboard button (partnership.php):
  Disabled with tooltip when no partner hostname is in master.conf.
  When partner configured but not onboarded, adds explanation note:
  "Onboard will generate your SSH key, exchange it with the partner..."
  No partner configured: "Edit master.conf and set HOST2."

Plugin/unraid/pages/monitor.php

@@ -579,6 +579,8 @@ function vvPollMonitor() {
             <span style="color:#444;">Uptime</span>
             <span style="color:#555;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;">${uptimeStr}</span>
           </div>${verWarn}`;
+        } else if (rs && rs.no_api_key) {
+          statsHtml = `<div style="font-size:10px;color:#444;margin-top:4px;">API key not configured — complete Onboard to enable</div>`;
         } else if (rs && !rs.available) {
           statsHtml = `<div style="font-size:10px;color:#444;margin-top:4px;">API unreachable</div>`;
         }