Fix: per-host error handling in sync loop

A single host failure (e.g. macro already exists, permission error)
was aborting the entire sync loop for all 310 hosts. Each host is
now wrapped in try/except — failures are logged as warnings and the
loop continues. Also logs when template is linked to an existing host.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/zabbix.py

@@ -200,12 +200,13 @@ def sync_to_zabbix(players, add_log_fn):
             log.warning("Template '%s' not found in Zabbix — import zabbix_template.yaml first", ZABBIX_TEMPLATE)
         existing = {h['host']: h for h in zbx.get_hosts_in_group(groupid)}
 
-        created = updated = 0
+        created = updated = skipped = 0
         for player in players:
             yid      = player['id']
             hostname = f"yodeck-{yid}"
             visible  = f"QRS-{player['name'][:4]}MB-{player['name'][4:]}"
 
+            try:
                 if hostname not in existing:
                     hostid = zbx.create_host(hostname, visible, groupid)
                     zbx.upsert_host_macro(hostid, '{$YODECK_ID}', str(yid))
@@ -217,18 +218,26 @@ def sync_to_zabbix(players, add_log_fn):
                     log.info("Created Zabbix host: %s (%s)", hostname, visible)
                 else:
                     h = existing[hostname]
+                    changed = False
                     if h['name'] != visible:
                         zbx.update_host_name(h['hostid'], visible)
-                    updated += 1
-                # Link template and set macro on existing hosts that don't have it yet
+                        changed = True
                     if template_id:
                         linked = {t['templateid'] for t in h.get('parentTemplates', [])}
                         if template_id not in linked:
                             zbx.upsert_host_macro(h['hostid'], '{$YODECK_ID}', str(yid))
                             zbx.link_template(h['hostid'], template_id)
+                            log.info("Linked template to existing host: %s", hostname)
+                            changed = True
+                    if changed:
                         updated += 1
+            except Exception as exc:
+                log.warning("Skipped host %s: %s", hostname, exc)
+                skipped += 1
 
-        msg = f"Zabbix sync complete: {created} created, {updated} updated ({len(players)} total)"
+        msg = (f"Zabbix sync complete: {created} created, {updated} updated"
+               + (f", {skipped} skipped" if skipped else "")
+               + f" ({len(players)} total)")
         add_log_fn('zabbix_sync', msg, {'created': created, 'updated': updated, 'total': len(players)})
         log.info(msg)