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>

libexec/devdesk-claude-run

@@ -36,9 +36,16 @@ common_args() {
 }
 
 run_new() {
-    local args
+    local args prompt=() file="$DEVDESK_STATE_DIR/prompts/$NAME.txt"
     mapfile -d '' args < <(common_args)
-    "$CLAUDE_BIN" -n "$NAME" "${args[@]}"
+    # A first prompt left by `devdesk attach --investigate` (Ops Alerts → Ask
+    # Claude, devdesk#39): sent once, right after the session name so options
+    # in CLAUDE_ARGS can't swallow it.
+    if [ -s "$file" ]; then
+        prompt=("$(cat "$file")")
+        rm -f "$file"
+    fi
+    "$CLAUDE_BIN" -n "$NAME" "${prompt[@]}" "${args[@]}"
 }
 
 run_resume() {