Add eagle-exec helper for blue-green deployments (#5567)

Adds a helper script that automatically runs docker exec against the
active Eagle instance (blue or green), determined by checking nginx
config.

Usage:
  eagle-exec printenv GEMINI_API_KEY
  eagle-exec jcmd 1 VM.flags
  eagle-exec sh

The script is deployed to /opt/eagle0/scripts/ and symlinked to
/usr/local/bin/eagle-exec for easy access.

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

scripts/eagle-exec.sh

@@ -0,0 +1,54 @@
+#!/bin/bash
+#
+# Helper to run docker exec against the active Eagle instance.
+# Automatically determines whether blue or green is active based on nginx config.
+#
+# Usage:
+#   ./scripts/eagle-exec.sh printenv GEMINI_API_KEY
+#   ./scripts/eagle-exec.sh jcmd 1 VM.flags
+#   ./scripts/eagle-exec.sh sh    # Get a shell
+#
+# Or create an alias:
+#   alias eagle-exec='/opt/eagle0/scripts/eagle-exec.sh'
+#
+
+set -euo pipefail
+
+APP_DIR="${APP_DIR:-/opt/eagle0}"
+
+# Determine active instance from nginx config
+get_active_instance() {
+    local backend
+    backend=$(docker exec nginx grep -o 'eagle-[a-z]*:40032' /etc/nginx/nginx.conf 2>/dev/null | head -1 || echo "")
+
+    if [ "$backend" = "eagle-blue:40032" ]; then
+        echo "eagle-blue"
+    elif [ "$backend" = "eagle-green:40032" ]; then
+        echo "eagle-green"
+    else
+        # Fallback: check which container is actually running
+        if docker inspect --format='{{.State.Running}}' eagle-blue 2>/dev/null | grep -q true; then
+            echo "eagle-blue"
+        elif docker inspect --format='{{.State.Running}}' eagle-green 2>/dev/null | grep -q true; then
+            echo "eagle-green"
+        else
+            echo ""
+        fi
+    fi
+}
+
+ACTIVE=$(get_active_instance)
+
+if [ -z "$ACTIVE" ]; then
+    echo "Error: No active Eagle instance found" >&2
+    exit 1
+fi
+
+if [ $# -eq 0 ]; then
+    echo "Active instance: $ACTIVE"
+    echo "Usage: $0 <command> [args...]"
+    echo "Example: $0 printenv GEMINI_API_KEY"
+    exit 0
+fi
+
+exec docker exec "$ACTIVE" "$@"