feat(monitoring): auto-prune Docker + node_modules, 15-min disk check interval

- check-disk-space.sh: always prune dangling images, unused volumes, and
  build cache >7 days on every run (not just at critical threshold)
- check-disk-space.sh: auto-remove node_modules if found on server
  (never needed — Docker builds inside containers)
- disk-check launchd: reduce interval from 60min to 15min to catch
  disk issues faster (yesterday we hit 100% before hourly check caught it)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/mac-mini/check-disk-space.sh

@@ -179,18 +179,33 @@ check_docker_disk() {
     local unused_volumes
     unused_volumes=$(docker volume ls -f "dangling=true" -q 2>/dev/null | wc -l | tr -d ' ')
 
-    if [ "$dangling_images" -gt 10 ] || [ "$unused_volumes" -gt 5 ]; then
-        log "Docker cleanup recommended: $dangling_images dangling images, $unused_volumes unused volumes"
+    log "Docker: $dangling_images dangling images, $unused_volumes unused volumes"
 
-        # Auto-cleanup if critical
-        local system_usage
-        system_usage=$(df -h / 2>/dev/null | awk 'NR==2 {gsub(/%/,""); print $5}')
+    # Always clean up dangling images (old build layers, no longer referenced)
+    if [ "$dangling_images" -gt 0 ]; then
+        log "Removing $dangling_images dangling images..."
+        docker image prune -f 2>/dev/null | tail -1
+    fi
 
-        if [ "$system_usage" -ge "$CRITICAL_THRESHOLD" ]; then
-            log "Running docker system prune due to critical disk usage..."
-            docker system prune -f --volumes 2>/dev/null || true
-            log "Docker cleanup completed"
-        fi
+    # Always clean up unused volumes (orphans from removed containers)
+    if [ "$unused_volumes" -gt 0 ]; then
+        log "Removing $unused_volumes unused volumes..."
+        docker volume prune -f 2>/dev/null | tail -1
+    fi
+
+    # Clean build cache older than 7 days
+    local build_cache
+    build_cache=$(docker system df --format '{{.Size}}' 2>/dev/null | tail -1)
+    log "Docker build cache: $build_cache"
+    docker builder prune -f --filter until=168h 2>/dev/null | tail -1
+
+    # Emergency: full prune if system disk critical
+    local system_usage
+    system_usage=$(df -h / 2>/dev/null | awk 'NR==2 {gsub(/%/,""); print $5}')
+    if [ "$system_usage" -ge "$CRITICAL_THRESHOLD" ]; then
+        log "CRITICAL disk usage at ${system_usage}% — running aggressive Docker cleanup..."
+        docker system prune -af --filter until=48h 2>/dev/null | tail -1
+        log "Aggressive cleanup completed"
     fi
 }
 
@@ -216,6 +231,21 @@ check_postgres_backups() {
     fi
 }
 
+check_stale_node_modules() {
+    # node_modules on the server is never needed — Docker builds inside containers
+    # If someone accidentally ran pnpm install, clean it up
+    local monorepo_nm="$PROJECT_ROOT/node_modules"
+    if [ -d "$monorepo_nm" ]; then
+        local nm_size
+        nm_size=$(du -sh "$monorepo_nm" 2>/dev/null | awk '{print $1}')
+        log "WARNING: Found node_modules on server (${nm_size}), removing..."
+        rm -rf "$monorepo_nm"
+        # Also remove nested node_modules
+        find "$PROJECT_ROOT" -name "node_modules" -type d -prune -exec rm -rf {} + 2>/dev/null || true
+        log "Removed all node_modules from server"
+    fi
+}
+
 check_docker_logs() {
     # Check for large Docker log files
     local docker_logs_dir="/var/lib/docker/containers"
@@ -262,7 +292,10 @@ fi
 # Push Colima VM disk metrics
 push_colima_metrics
 
-# Check Docker disk usage
+# Remove accidental node_modules on server
+check_stale_node_modules
+
+# Check Docker disk usage + auto-prune
 check_docker_disk
 
 # Check backup sizes

scripts/mac-mini/launchd/com.manacore.disk-check.plist

@@ -11,9 +11,9 @@
         <string>/Users/mana/projects/manacore-monorepo/scripts/mac-mini/check-disk-space.sh</string>
     </array>
 
-    <!-- Run hourly -->
+    <!-- Run every 15 minutes — frequent enough to catch disk issues early -->
     <key>StartInterval</key>
-    <integer>3600</integer>
+    <integer>900</integer>
 
     <!-- Also run at startup -->
     <key>RunAtLoad</key>