feat: v0.9.2 Ask Claude on an alert starts an investigation session

- Ops Alerts → Ask Claude now calls `devdesk attach --investigate SESSION UID`.
  The server looks the alert up, writes the prompt and starts Claude in a new
  alert-<name> session with it as the first prompt, already sent. Prompts are
  stored in prompts/<session>.txt and consumed once by devdesk-claude-run.
  A session that is already running is just opened.
- The prompt has the rule, query, summary, details and labels, and where it
  runs: the CT/VM id, the node it is on now, status and HA state, and
  `ssh <node> pct exec <id> --`. It reminds Claude that HA guests move
  (`devdesk guests <id>`), and gives aggregate rules a hint.
- `devdesk guests`: Proxmox inventory over SSH (DEVDESK_PVE_NODES). pvesh
  gives the cluster view; each node gives lxc-info and guest-agent IPs.
  Cached in guests.json, keeping last-seen IPs for stopped guests; --alerts
  refreshes it in the background every 5 minutes.
- Alerts carry uid, query, description and targets, matched by instance
  IP/host or by name; each card shows the target.
- cmd_alerts moves to libexec/devdesk-ops.sh.

Closes #39

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/alerts.js

@@ -1,8 +1,10 @@
 // Ops Alerts panel: firing/pending Grafana alert rules (`devdesk attach --alerts`),
-// each with an "Ask Claude" button that types an investigation prompt into the
-// current session (without pressing Enter).
+// the Proxmox guest or node each is about (CT id, the node it runs on now), and
+// an "Ask Claude" button that starts an investigation in a session of its own
+// (devdesk#39).
 
 import { el } from './dom.js';
+import { slugify } from './protocol.js';
 
 const SEVERITY = {
   critical: 'lt-chip-critical',
@@ -18,14 +20,24 @@ function age(iso) {
   return `${Math.floor(s / 86400)}d`;
 }
 
-export function investigatePrompt(alert) {
-  const where = alert.instances?.length ? ` on ${alert.instances.join('; ')}` : '';
-  return `Investigate the ${alert.state} Grafana alert "${alert.name}"`
-    + ` (${alert.severity || 'no severity'}, ${alert.folder} / ${alert.group}${where}, since ${alert.since}).`
-    + ` Summary: ${alert.summary || 'n/a'}. Use the grafana MCP server to look at the rule and the related`
-    + ' metrics, find the cause, and tell me what you would change before changing anything.';
+// "CT 110 draupnir · monitor-02 · stopped", "node compute-storage-01".
+function targetLabel(t) {
+  if (t.kind === 'unknown') return null;
+  const what = t.kind === 'node' ? `node ${t.name}` : `${t.kind.toUpperCase()} ${t.id} ${t.name}`;
+  const parts = [what, t.kind === 'node' ? null : t.node, t.status === 'running' || t.status === 'online' ? null : t.status];
+  return parts.filter(Boolean).join(' · ') + (t.by === 'name' ? ' (by name)' : '');
 }
 
+function targetTitle(t) {
+  const how = t.kind === 'ct' ? `ssh ${t.node} pct exec ${t.id} -- …`
+    : t.kind === 'vm' ? `ssh ${t.node} qm guest exec ${t.id} -- …` : `ssh ${t.name}`;
+  const note = t.by === 'name' ? '\nMatched by name, not by IP (the guest has not been seen running with this IP).'
+    : t.ip_seen ? '\nIts IP when it was last seen running.' : '';
+  return `${how}${t.ha ? `\nHA state: ${t.ha}` : ''}${note}`;
+}
+
+export const alertSession = (alert) => slugify(`alert-${alert.name}`).toLowerCase().slice(0, 48) || 'alert';
+
 export function renderAlerts(root, data) {
   const list = root.querySelector('.dd-alert-list');
   const note = root.querySelector('.dd-alerts-note');
@@ -59,11 +71,14 @@ export function renderAlerts(root, data) {
       el('a', { class: 'dd-alert-name', href: a.url, target: '_blank', rel: 'noopener', title: `${a.folder} / ${a.group}` }, a.name),
       el('span', { class: 'dd-muted dd-alert-age' }, age(a.since))),
     a.instances?.length ? el('div', { class: 'dd-muted dd-alert-instances' }, a.instances.join(' · ')) : null,
+    ...(a.targets ?? []).map((t) => {
+      const label = targetLabel(t);
+      return label ? el('div', { class: `dd-alert-where${t.by === 'name' ? ' is-guess' : ''}`, title: targetTitle(t) }, label) : null;
+    }),
     a.summary ? el('div', { class: 'dd-alert-summary' }, a.summary) : null,
     el('div', { class: 'dd-ask-row' },
-      el('button', { type: 'button', class: 'lt-btn lt-btn-sm dd-ask', 'data-ask-claude': investigatePrompt(a), title: 'Type the prompt into the current session (not sent)' }, 'Ask Claude'),
       el('button', {
-        type: 'button', class: 'lt-btn lt-btn-ghost lt-btn-sm dd-ask', 'data-ask-claude': investigatePrompt(a),
-        'data-ask-session': `alert-${a.name}`, title: 'Open a separate ops session for this alert and type the prompt there (not sent)',
-      }, 'In a new session')))));
+        type: 'button', class: 'lt-btn lt-btn-sm dd-ask', 'data-investigate': a.uid, 'data-session': alertSession(a),
+        title: `Start Claude in a new session (${alertSession(a)}) on this alert, with the rule, the query and where it runs (CT id, node)`,
+      }, 'Ask Claude')))));
 }