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/storage/filesystem/filesystem_test.go

@@ -531,8 +531,8 @@ func (s *FilesystemStorageTestSuite) TestConcurrentReadsAndWrites() {
 				key := fmt.Sprintf("shared/file-%d.txt", j%10)
 				reader, err := s.fs.Get(ctx, key)
 				if err == nil {
-					io.ReadAll(reader)
-					reader.Close() // #nosec G104 -- Cleanup, error not critical
+					_, _ = io.ReadAll(reader)
+					_ = reader.Close() // #nosec G104 -- Cleanup, error not critical
 				}
 			}
 		}(i)
@@ -546,7 +546,7 @@ func (s *FilesystemStorageTestSuite) TestConcurrentReadsAndWrites() {
 			for j := 0; j < numOps; j++ {
 				key := fmt.Sprintf("shared/writer-%d-%d.txt", id, j)
 				data := fmt.Sprintf("writer-%d-%d", id, j)
-				s.fs.Put(ctx, key, strings.NewReader(data), nil)
+				_ = s.fs.Put(ctx, key, strings.NewReader(data), nil)
 			}
 		}(i)
 	}
@@ -608,15 +608,15 @@ func (s *FilesystemStorageTestSuite) TestAtomicWrite() {
 				case <-stopReading:
 					return
 				default:
-					reader, err := s.fs.Get(ctx, key)
-					if err != nil {
-						readErrors <- err
+					reader, getErr := s.fs.Get(ctx, key)
+					if getErr != nil {
+						readErrors <- getErr
 						continue
 					}
-					data, err := io.ReadAll(reader)
+					data, readErr := io.ReadAll(reader)
 					reader.Close() // #nosec G104 -- Cleanup, error not critical
-					if err != nil {
-						readErrors <- err
+					if readErr != nil {
+						readErrors <- readErr
 						continue
 					}
 					// Data should be either "initial" or "updated", never partial
@@ -663,7 +663,8 @@ func (s *FilesystemStorageTestSuite) TestPathSanitization() {
 			s.NoError(err) // Should succeed but sanitize path
 
 			// Verify file is inside base directory
-			sanitized := s.fs.keyToPath(path)
+			sanitized, sanitizeErr := s.fs.keyToPath(path)
+			s.NoError(sanitizeErr)
 			s.True(strings.HasPrefix(sanitized, s.tempDir),
 				"Sanitized path %s should be inside %s", sanitized, s.tempDir)
 		})
@@ -728,7 +729,7 @@ func BenchmarkFilesystemPut(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		key := fmt.Sprintf("bench/file-%d.txt", i)
-		fs.Put(ctx, key, strings.NewReader(data), nil)
+		_ = fs.Put(ctx, key, strings.NewReader(data), nil)
 	}
 }
 
@@ -744,14 +745,14 @@ func BenchmarkFilesystemGet(b *testing.B) {
 	data := strings.Repeat("x", 1024)
 
 	// Setup: Create test file
-	fs.Put(ctx, "bench/test.txt", strings.NewReader(data), nil)
+	_ = fs.Put(ctx, "bench/test.txt", strings.NewReader(data), nil)
 
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		reader, _ := fs.Get(ctx, "bench/test.txt")
 		if reader != nil {
-			io.ReadAll(reader)
-			reader.Close() // #nosec G104 -- Cleanup, error not critical
+			_, _ = io.ReadAll(reader)
+			_ = reader.Close() // #nosec G104 -- Cleanup, error not critical
 		}
 	}
 }