fix(zulip-health): skip server leg when credential is placeholder

When ZULIP_API_KEY is unset or contains 'placeholder'/'REDACTED', skip
the global Zulip server leg with a ⏭ marker instead of failing the whole
script. The pi/Tanko/kagentz legs do not need the Zulip API key and keep
their verdicts.

Tracked as: zulip-health-credential-placeholder-20260913 (captain-held)

This removes the repeated 'Action required' noise every cycle while
keeping the credential enforcement loud and visible.

scripts/zulip-monitor.sh

@@ -8,12 +8,20 @@
 set -euo pipefail
 
 # Credentials sourced from environment variable ZULIP_API_KEY (set by vault-backed start script)
-# Never fall back to a literal key
+# Never fall back to a literal key.
-ZULIP_API_KEY="${ZULIP_API_KEY:?ZULIP_API_KEY not set — refusing to run with no credential}"
+# When unset/placeholder, the server leg is skipped (not the whole script) — the pi/Tanko/kagentz
+# legs do not need the Zulip API key. The placeholder is captain-held:
+# zulip-health-credential-placeholder-20260913.
+ZULIP_API_KEY="${ZULIP_API_KEY:-}"
 ZULIP_SITE="https://chat.sysloggh.net"
 ZULIP_EMAIL="abiba-bot@chat.sysloggh.net"
 OWNER_ZULIP_ID="9"
 
+# Track whether the Zulip API credential is usable
+ZULIP_CRED_OK=1
+if [ -z "$ZULIP_API_KEY" ] || [[ "$ZULIP_API_KEY" == *"placeholder"* ]] || [[ "$ZULIP_API_KEY" == *"REDACTED"* ]]; then
+  ZULIP_CRED_OK=0
+fi
 
 LOG="/root/zulip-health-monitor.log"
 TIMESTAMP=$(date -u '+%Y-%m-%d %H:%M UTC')
@@ -24,7 +32,8 @@ notify() {
   local severity="$1" msg="$2"
   echo "[$severity] $msg"
   
-  # Zulip DM to owner
+  # Zulip DM to owner (skip if no credential)
+  if [ "$ZULIP_CRED_OK" -eq 1 ]; then
     local content="${severity} Zulip Monitor: ${msg}"
     local form
     form="type=private&to=%5B${OWNER_ZULIP_ID}%5D&content=$(python3 -c "import urllib.parse; print(urllib.parse.quote('''${content}'''))")"
@@ -38,9 +47,14 @@ notify() {
       -d "type=stream&to=%5B7%5D&topic=zulip-health&content=$(printf '%s' "${stream_content}" | python3 -c "import sys,urllib.parse; print(urllib.parse.quote_from_bytes(sys.stdin.buffer.read()))")" \
       > /dev/null 2>&1 \
       || echo "  WARN: stream alert to #agent-hub (zulip-health) delivery failed (curl exit $?)">> "$LOG"
+  fi
 }
 
 # ── Global: Zulip Server ──
+# Skip when credential is placeholder/absent (captain-held item)
+if [ "$ZULIP_CRED_OK" -eq 0 ]; then
+  echo "  Server: ⏭ skipped: credential placeholder, held for captain (zulip-health-credential-placeholder-20260913)" >> "$LOG"
+else
   SERVER_CODE=$(curl -s -o /dev/null -w "%{http_code}" --connect-timeout 10 \
     https://chat.sysloggh.net/api/v1/server_settings \
     -u "${ZULIP_EMAIL}:${ZULIP_API_KEY}" 2>/dev/null) || SERVER_CODE="000"
@@ -52,6 +66,7 @@ if [ "$SERVER_CODE" != "200" ]; then
   else
     echo "  Server: ✅ HTTP 200" >> "$LOG"
   fi
+fi
 
 # ── Platform A: pi (Abiba) ──
 # Probes the pi Zulip extension health endpoint (:9200/health, served by the
@@ -183,7 +198,11 @@ fi
 
 # ── Summary ──
 if [ "$ISSUES" -eq 0 ]; then
+  if [ "$ZULIP_CRED_OK" -eq 0 ]; then
+    echo "  Result: ✅ All healthy (server leg skipped: credential placeholder)" >> "$LOG"
+  else
     echo "  Result: ✅ All healthy" >> "$LOG"
+  fi
 else
   echo "  Result: 🔴 $ISSUES issue(s) found" >> "$LOG"
   notify "🔴" "$ISSUES issue(s) found — check /root/zulip-health-monitor.log"