feat: comprehensive audit + Tier 3 wiring (security/correctness/features)

Multi-agent audit + fix pass covering bugs, security, dead config wiring,
and missing features. All quality gates green: build/vet/test -race/govulncheck/
golangci-lint. Frontend tests 47/47.

SECURITY & CORRECTNESS

- Scanner pipeline fail-closed: cache.go scan timeout now 503 (was goto servePkg);
  scanner.go all-scanners-fail saves ScanStatusError; CheckVulnerabilities blocks
  on missing/error result instead of allowing.
- Scanner argv corrections: govulncheck source-mode + go.mod discovery;
  npm-audit generates lockfile via npm install --package-lock-only --ignore-scripts;
  pip-audit per-extension dispatch (wheel direct / sdist extract+pyproject).
- GHSA version-range filtering implemented (was always-include); url.QueryEscape
  on package name.
- pypi SSRF closed via host allowlist on original_url; url.QueryEscape on
  rewriteURL output.
- Path traversal: cache temp file uses os.CreateTemp; smb keyToPath sanitized;
  filesystem keyToPath returns error + filepath.Abs prefix-verify.
- Goroutine leaks plugged: cache.cleanupWorker stop channel; auth.ValidationCache
  Stop() with sync.Once; ws.unregister buffered with non-blocking send.
- WebSocket double-close panic fixed via sync.Once Client.closeSend().
- Race conditions: gormstore.registryCache sync.RWMutex (was concurrent map
  panic); auth.LastUsedAt no longer mutated under RLock; analytics strict
  lock-ordering invariant (statsMu before downloadsMu).
- Auth validator fails CLOSED on transport/unknown-status errors (was returning
  true,err 'allow cache fallback').
- Credential cache hash full SHA256 (was 8-byte truncate; eliminates 2^32
  collision risk).
- filesystem.fs.used incremented after successful rename (no quota inflation
  race).
- gormstore aggregation events deleted in same tx as insert (no double-counting).
- gormstore.SavePackage uses Updates(map) so zero-value security flags
  (RequiresAuth=false) can be cleared.
- partition_manager validates partition name regex before DROP TABLE.
- vcs/git: version regex validation rejects --option-injection; checkout uses
  --detach -- separator; removed TrimPrefix(repo,'v') that corrupted vault/
  vitess/vim-go.
- WebSocket CheckOrigin allowlist (was return true; CSWSH closed); same-origin
  default + ServerConfig.AllowedOrigins.
- fiber CVE GO-2026-4543 patched (v2.52.10 -> v2.52.12).

FUNCTIONAL FEATURES

- API key DB persistence: APIKeyModel + migration 202604280002, full CRUD,
  async LastUsedAt updates with WaitGroup-tracked goroutines drained on Close.
- Admin bootstrap via GOHOARDER_BOOTSTRAP_ADMIN_KEY env var; idempotent
  (skipped when non-revoked admin already exists).
- Auth middleware factory in pkg/app: RequireAuth, RequireRole, RequirePermission,
  OptionalAuth. Mounted on proxy + read APIs when Auth.Enabled=true.
  DELETE /api/packages/* requires admin role. /health public for k8s probes.
- NFS storage backend: pkg/storage/nfs wraps filesystem with /proc/mounts
  detection (Linux), post-write fsync, read-after-write health probe.
- WebSocket real-time pipeline: pkg/events Broadcaster interface; cache + scanner
  managers emit EventPackageCached / EventPackageDownloaded / EventScanComplete;
  app.go runs 30s EventStatsUpdate ticker. Frontend has full WS client (reconnect
  with exponential backoff 1s->30s, 25s heartbeat, subscriber pattern), Pinia
  realtime store, Dashboard live indicator + activity feed + reactive stats
  override.
- TLS termination: fiber.ListenTLS when Server.TLS.Enabled.
- Pre-warming: Prewarming.Enabled flag wired (was hardcoded false); Interval,
  MaxConcurrent, TopPackages plumbed.
- NetworkConfig wired (timeouts, retry, rate-limit, circuit-breaker).
- AuthConfig.BcryptCost wired.
- Security.Scanners.Static.MaxPackageSize plumbed to cache.io.LimitReader.
- Handlers.{Go,NPM,PyPI}.Enabled gates route mounting.
- Graceful shutdown: authManager.Close drains async writes.

LINT/HYGIENE

- 80 golangci-lint issues resolved: errcheck (Close/Write/RemoveAll wrapped),
  gofmt, gosec G104/G306, govet shadow renames + fieldalignment reorders,
  staticcheck ST1000 pkg comments + QF1003 tagged switches + QF1008 embedded
  field selectors + QF1001 De Morgan's law.

BEHAVIOR CHANGES

- Scanner now fail-closed: deployments without scanner binaries
  (trivy/govulncheck/npm-audit/pip-audit/grype) BLOCK packages instead of
  serving unscanned. Add binaries or plan a future allow-on-scan-error flag.
- WS origin defaults to same-origin; cross-origin dashboards must set
  server.allowed_origins.
- Validator no longer fails open; private packages won't serve from cache when
  validation can't be performed.
- download_events retention dropped from 24h to ~5min (deleted in agg tx).
  Migration 202604280001 purges pre-upgrade events.
- DELETE /api/packages/* requires admin role when auth enabled.

NEW PACKAGES

- pkg/events  - Broadcaster interface
- pkg/storage/nfs  - NFS-aware filesystem wrapper

DEFERRED (out of scope this pass)

- Static scanner implementation (config defines AllowedLicenses/MaxPackageSize/
  BlockSuspicious but pkg/scanner/static/ does not exist).
- AuthConfig.AuditLog wiring (no audit log infra yet).
- CacheConfig.TTLOverrides passthrough (would touch cache.Config beyond
  integrator scope).

pkg/auth/validation_cache.go

@@ -14,16 +14,20 @@ type ValidationResult struct {
 
 // ValidationCache caches credential validation results to reduce upstream checks
 type ValidationCache struct {
-	cache map[string]*ValidationResult
-	mu    sync.RWMutex
-	ttl   time.Duration
+	cache    map[string]*ValidationResult
+	stopCh   chan struct{}
+	stopOnce sync.Once
+	mu       sync.RWMutex
+	ttl      time.Duration
 }
 
-// NewValidationCache creates a new validation cache
+// NewValidationCache creates a new validation cache. Callers must call Stop()
+// during shutdown to terminate the background cleanup goroutine.
 func NewValidationCache(ttl time.Duration) *ValidationCache {
 	vc := &ValidationCache{
-		cache: make(map[string]*ValidationResult),
-		ttl:   ttl,
+		cache:  make(map[string]*ValidationResult),
+		stopCh: make(chan struct{}),
+		ttl:    ttl,
 	}
 
 	// Start cleanup goroutine
@@ -32,25 +36,42 @@ func NewValidationCache(ttl time.Duration) *ValidationCache {
 	return vc
 }
 
+// Stop terminates the background cleanup goroutine. Safe to call multiple
+// times; subsequent calls are no-ops.
+func (vc *ValidationCache) Stop() {
+	vc.stopOnce.Do(func() {
+		close(vc.stopCh)
+	})
+}
+
 // Get retrieves a validation result from cache
 // Returns (allowed bool, cached bool, reason string)
 func (vc *ValidationCache) Get(credHash, packageURL string) (bool, bool, string) {
-	vc.mu.RLock()
-	defer vc.mu.RUnlock()
-
 	key := credHash + ":" + packageURL
+
+	// Fast path: read-locked lookup.
+	vc.mu.RLock()
 	result, exists := vc.cache[key]
-
 	if !exists {
+		vc.mu.RUnlock()
 		return false, false, ""
 	}
-
-	// Check if expired
-	if time.Now().After(result.ExpiresAt) {
-		return false, false, ""
+	expired := time.Now().After(result.ExpiresAt)
+	if !expired {
+		allowed, reason := result.Allowed, result.Reason
+		vc.mu.RUnlock()
+		return allowed, true, reason
 	}
+	vc.mu.RUnlock()
 
-	return result.Allowed, true, result.Reason
+	// Expired: drop it under the write lock so callers don't all stampede
+	// the upstream while waiting for the periodic cleanup goroutine.
+	vc.mu.Lock()
+	if cur, ok := vc.cache[key]; ok && time.Now().After(cur.ExpiresAt) {
+		delete(vc.cache, key)
+	}
+	vc.mu.Unlock()
+	return false, false, ""
 }
 
 // Set stores a validation result in cache
@@ -91,19 +112,25 @@ func (vc *ValidationCache) Size() int {
 	return len(vc.cache)
 }
 
-// cleanupExpired removes expired entries periodically
+// cleanupExpired removes expired entries periodically. Exits when Stop is
+// called.
 func (vc *ValidationCache) cleanupExpired() {
 	ticker := time.NewTicker(1 * time.Minute)
 	defer ticker.Stop()
 
-	for range ticker.C {
-		vc.mu.Lock()
-		now := time.Now()
-		for key, result := range vc.cache {
-			if now.After(result.ExpiresAt) {
-				delete(vc.cache, key)
+	for {
+		select {
+		case <-vc.stopCh:
+			return
+		case <-ticker.C:
+			vc.mu.Lock()
+			now := time.Now()
+			for key, result := range vc.cache {
+				if now.After(result.ExpiresAt) {
+					delete(vc.cache, key)
+				}
 			}
+			vc.mu.Unlock()
 		}
-		vc.mu.Unlock()
 	}
 }