fix: three wrapper holes in contract-run.sh

1. Add disk-gc-threat-response to case statement (was only in header comment,
   hit *) branch and exited 2 silently). Mapped to scripts/disk-gc-scan.py per
   contract's Execution section.

2. Apply timeout to script invocation (was defined as TIMEOUT=600 but never used,
   so a hung check blocked the cron slot forever). Now wrapped with timeout, and
   exit 124 (timeout kill) logs a TIMEOUT line before the FAIL verdict.

3. Send alert on exit-2 paths (unknown contract and missing script). Both paths
   previously just echoed and exited, so a typo'd name or absent script was a
   silent monitoring loss. Now they send the same Zulip DM as a failed check.

Proved all four paths with raw output:
- unknown contract: curl -sf attempted, exit 22 on HTTP 401
- missing script: curl -sf attempted, exit 2
- disk-gc-threat-response: resolves to disk-gc-scan.py, runs, PASS
- stub sleep > timeout: TIMEOUT line logged, exit 1, alert failure recorded

scripts/contract-run.sh

@@ -61,8 +61,24 @@ case "$CONTRACT_NAME" in
         SCRIPT_PATH="${SCRIPTS_DIR}/pm2-self-heal.sh"
         INTERPRETER="bash"
         ;;
+    disk-gc-threat-response)
+        SCRIPT_PATH="${SCRIPTS_DIR}/disk-gc-scan.py"
+        INTERPRETER="python3"
+        ;;
     *)
         echo "Unknown contract: $CONTRACT_NAME" | tee -a "$LOG_FILE"
+        # Send alert for unknown contract
+        ALERT_MSG="🔴 Contract $CONTRACT_NAME: unknown contract name. Log: $LOG_FILE"
+        ZULIP_API_URL="${ZULIP_API_URL:-https://chat.sysloggh.net/api/v1}"
+        ZULIP_API_KEY="${ZULIP_API_KEY:-}"
+        ZULIP_USER="${ZULIP_USER:-abiba-bot@chat.sysloggh.net}"
+        if [ -n "$ZULIP_API_KEY" ] && command -v curl &> /dev/null; then
+            curl -sf -X POST "${ZULIP_API_URL}/messages" \
+                -u "${ZULIP_USER}:${ZULIP_API_KEY}" \
+                -d "type=private" \
+                -d "to=9" \
+                -d "content=${ALERT_MSG}" > /dev/null 2>&1 || true
+        fi
         exit 2
         ;;
 esac
@@ -70,6 +86,18 @@ esac
 # Check if script exists
 if [ ! -f "$SCRIPT_PATH" ]; then
     echo "Script not found: $SCRIPT_PATH" | tee -a "$LOG_FILE"
+    # Send alert for missing script
+    ALERT_MSG="🔴 Contract $CONTRACT_NAME: script not found at $SCRIPT_PATH. Log: $LOG_FILE"
+    ZULIP_API_URL="${ZULIP_API_URL:-https://chat.sysloggh.net/api/v1}"
+    ZULIP_API_KEY="${ZULIP_API_KEY:-}"
+    ZULIP_USER="${ZULIP_USER:-abiba-bot@chat.sysloggh.net}"
+    if [ -n "$ZULIP_API_KEY" ] && command -v curl &> /dev/null; then
+        curl -sf -X POST "${ZULIP_API_URL}/messages" \
+            -u "${ZULIP_USER}:${ZULIP_API_KEY}" \
+            -d "type=private" \
+            -d "to=9" \
+            -d "content=${ALERT_MSG}" > /dev/null 2>&1 || true
+    fi
     exit 2
 fi
 
@@ -81,9 +109,14 @@ echo "" | tee -a "$LOG_FILE"
 
 # Use timeout to prevent hangs (10 minutes default)
 TIMEOUT=600
-$INTERPRETER "$SCRIPT_PATH" 2>&1 | tee -a "$LOG_FILE"
+timeout "$TIMEOUT" $INTERPRETER "$SCRIPT_PATH" 2>&1 | tee -a "$LOG_FILE"
 EXIT_CODE=${PIPESTATUS[0]}
 
+# If timeout killed the process, EXIT_CODE will be 124
+if [ $EXIT_CODE -eq 124 ]; then
+    echo "⏰ TIMEOUT: script exceeded ${TIMEOUT}s limit" | tee -a "$LOG_FILE"
+fi
+
 echo "" | tee -a "$LOG_FILE"
 if [ $EXIT_CODE -eq 0 ]; then
     echo "✅ VERDICT: PASS" | tee -a "$LOG_FILE"