chore(lint): Backlog auf 0 + golangci-lint als HARTER Gate — v1.3.3

Go-Quality-Baseline-Rollout ABGESCHLOSSEN.

Code-Quality-Backlog (55 → 0):
- errcheck: unbehandelte Close/Rollback/Remove explizit `_ =`; fmt.Sscanf
  `_, _ =` (Zero-Value degradiert sauber).
- unused: toter Code entfernt (nodeIDOrHostname, stripTrailingNewline,
  acme.Service.user, strFold + ungenutzter Import).
- noctx (net/http): http.NewRequestWithContext mit vorhandenem ctx.
- staticcheck: QF1001/S1009/ST1005/SA9003.
- contextcheck: detached-by-design-Stellen mit begründetem //nolint.

Zwei echte Bugs beim Aufräumen gefunden+gefixt:
- backup/remote SFTP-Upload: dst.Close()-Flush-Fehler wurde verschluckt →
  unvollständiges Remote-File galt als Erfolg. Jetzt geprüft+gemeldet.
- haproxy_test: leere if-Assertion (SA9003) testete faktisch nichts →
  echte t.Errorf-Prüfung (kein HSTS für HSTS-disabled Domain).

Bewusste Config-Entscheidungen (.golangci.yml):
- noctx-on-os/exec ausgeschlossen: System-Command-Reloads (systemctl/nft/
  wg/pg) dürfen NICHT an den Request-Context gebunden werden — ein Client-
  Disconnect darf keinen laufenden Reload mitten in der Ausführung killen.
  net/http-noctx bleibt voll aktiv. KEINE exec-Zeile im Code angefasst.
- rowserrcheck/sqlclosecheck raus (database/sql-Linter, bei pgx nur FPs).

Gate scharf gestellt: Makefile release-check ruft golangci-lint jetzt als
HARTEN Gate (install-if-missing, pinned v2.12.2). `make release-check`
grün: vet, golangci-lint, govulncheck, build, test -race.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

cmd/edgeguard-api/main.go

@@ -687,30 +687,6 @@ func openDBBestEffort() (*pgxpoolPool, error) {
 // main.go on every platform — keeps the import block lean.
 type pgxpoolPool = pgxpool.Pool
 
-// nodeIDOrHostname returns the node identifier audit_log entries are
-// stamped with. v1 just uses /etc/machine-id (or the hostname on dev
-// machines without one). Phase 3's cluster store will replace this.
-func nodeIDOrHostname() string {
-	if b, err := os.ReadFile("/etc/machine-id"); err == nil {
-		s := string(b)
-		s = stripTrailingNewline(s)
-		if s != "" {
-			return s
-		}
-	}
-	if h, err := os.Hostname(); err == nil {
-		return h
-	}
-	return "unknown"
-}
-
-func stripTrailingNewline(s string) string {
-	for len(s) > 0 && (s[len(s)-1] == '\n' || s[len(s)-1] == '\r') {
-		s = s[:len(s)-1]
-	}
-	return s
-}
-
 // randomEphemeralSecret is the fallback for dev environments where
 // /var/lib/edgeguard isn't writable. Tokens issued with this secret
 // die on restart — production reads/writes the persistent file via
@@ -869,7 +845,7 @@ func runPrimaryPush(ctx context.Context, pool *pgxpoolPool, nodeID, fqdn, versio
 		pCtx, cancel := context.WithTimeout(ctx, 15*time.Second)
 		defer cancel()
 		hash, _ := cluster.ComputeConfigHash(pCtx, pool)
-		if err := clusterjoin.PushSelfToPrimary(primaryURL, "", nodeID, fqdn, version, hash); err != nil {
+		if err := clusterjoin.PushSelfToPrimary(primaryURL, "", nodeID, fqdn, version, hash); err != nil { //nolint:contextcheck // detached by design — Heartbeat-Push nutzt eigenen Timeout, überlebt Request-Cancel
 			slog.Warn("cluster: push-to-primary failed", "error", err)
 		} else {
 			slog.Debug("cluster: config_hash pushed to primary", "hash", hash)
@@ -915,7 +891,7 @@ func runPeerPush(ctx context.Context, pool *pgxpoolPool, store *cluster.Store, n
 			if target == "" {
 				target = "https://" + p.FQDN
 			}
-			if err := clusterjoin.PushSelfToPeer(target, "", nodeID, fqdn, version, hash, "primary"); err != nil {
+			if err := clusterjoin.PushSelfToPeer(target, "", nodeID, fqdn, version, hash, "primary"); err != nil { //nolint:contextcheck // detached by design — Heartbeat-Push nutzt eigenen Timeout, überlebt Request-Cancel
 				slog.Debug("cluster: push-to-peer failed", "peer", p.FQDN, "error", err)
 			}
 		}

cmd/edgeguard-ctl/cluster_replication.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"crypto/rand"
 	"crypto/tls"
 	"crypto/x509"
@@ -319,9 +320,11 @@ host replication %s ::/0      scram-sha-256
 	if err != nil {
 		return fmt.Errorf("open: %w", err)
 	}
-	defer f.Close()
-	_, err = f.WriteString(entry)
-	return err
+	if _, err = f.WriteString(entry); err != nil {
+		_ = f.Close()
+		return err
+	}
+	return f.Close()
 }
 
 // cmdClusterSetupStandby richtet diesen Node als Logical-Replication-
@@ -497,11 +500,15 @@ func fetchReplicationCreds(host string, agentPort int, tlsDir string) (*pgReplic
 	}
 
 	url := "https://" + net.JoinHostPort(host, strconv.Itoa(agentPort)) + "/agent/cluster/pg-replication-info"
-	resp, err := client.Get(url)
+	req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, url, nil)
 	if err != nil {
 		return nil, fmt.Errorf("GET %s: %w", url, err)
 	}
-	defer resp.Body.Close()
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("GET %s: %w", url, err)
+	}
+	defer func() { _ = resp.Body.Close() }()
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("GET %s: HTTP %d", url, resp.StatusCode)
 	}
@@ -543,11 +550,15 @@ func syncMasterKey(host string, agentPort int, tlsDir string) error {
 		},
 	}
 	url := "https://" + net.JoinHostPort(host, strconv.Itoa(agentPort)) + "/agent/cluster/master-key"
-	resp, err := client.Get(url)
+	req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, url, nil)
 	if err != nil {
 		return fmt.Errorf("GET %s: %w", url, err)
 	}
-	defer resp.Body.Close()
+	resp, err := client.Do(req)
+	if err != nil {
+		return fmt.Errorf("GET %s: %w", url, err)
+	}
+	defer func() { _ = resp.Body.Close() }()
 	if resp.StatusCode != http.StatusOK {
 		return fmt.Errorf("GET %s: HTTP %d", url, resp.StatusCode)
 	}

cmd/edgeguard-ctl/initdb.go

@@ -93,7 +93,7 @@ func looksLikeIdentifier(s string) bool {
 	if s == "" || len(s) > 63 {
 		return false
 	}
-	if !(s[0] == '_' || (s[0] >= 'a' && s[0] <= 'z')) {
+	if s[0] != '_' && (s[0] < 'a' || s[0] > 'z') {
 		return false
 	}
 	for _, r := range s[1:] {

cmd/edgeguard-scheduler/main.go

@@ -567,7 +567,7 @@ func parseChronyTrackingForAlert(out string) (synced bool, stratum int, referenc
 				synced = true
 			}
 		case "Stratum":
-			fmt.Sscanf(val, "%d", &stratum)
+			_, _ = fmt.Sscanf(val, "%d", &stratum)
 			if stratum > 0 && stratum < 16 {
 				synced = true
 			} else if stratum == 0 || stratum >= 16 {
@@ -670,13 +670,14 @@ func runBackendDownCheck(ctx context.Context, pool *pgxpool.Pool, a *alerts.Serv
 	if a == nil || d == nil {
 		return
 	}
-	conn, err := net.DialTimeout("unix", "/run/haproxy/admin.sock", 2*time.Second)
+	dialer := net.Dialer{Timeout: 2 * time.Second}
+	conn, err := dialer.DialContext(ctx, "unix", "/run/haproxy/admin.sock")
 	if err != nil {
 		// HAProxy läuft nicht oder Socket nicht erreichbar — kein Alert,
 		// das ist der Dienst selbst nicht der Scheduler.
 		return
 	}
-	defer conn.Close()
+	defer func() { _ = conn.Close() }()
 	_ = conn.SetDeadline(time.Now().Add(3 * time.Second))
 	if _, err := conn.Write([]byte("show stat\n")); err != nil {
 		return
@@ -1019,7 +1020,7 @@ func runLicenseVerify(ctx context.Context, c *license.Client, ks *license.KeySto
 		slog.Debug("scheduler: license verify skipped — no key")
 		return
 	}
-	res, err := c.Verify(key)
+	res, err := c.Verify(key) //nolint:contextcheck // detached by design — License-Verify nutzt eigenen HTTP-Timeout, überlebt Request-Cancel
 	if err != nil {
 		_ = repo.MarkError(ctx, key, err.Error())
 		slog.Warn("scheduler: license verify failed", "error", err)