Remediate all lint findings under the canonical golangci-lint config

Fix every finding surfaced by the canonical .golangci.yml with
golangci-lint v2.12.2 (refs #61), behavior-preserving throughout:

- err113: dynamic errors replaced with package-level sentinels and %w
  wrapping; direct comparisons converted to errors.Is
- goprintffuncname: printf-style helpers renamed with an f suffix
  (ui.Writer message methods, cli.ReportErrorf, database.Fatalf,
  vaultik stdoutf) and all call sites updated
- revive: stuttering type names renamed (blob.Handler, blob.WithReader,
  blob.ChunkPosition, storage.URL, storage.Info), doc comments added,
  unused parameters blanked, package comments added
- contextcheck/noctx: ctx threaded through blob.Packer
  (AddChunk/Flush/FinalizeBlob/PackChunks) and scanner call sites;
  context-aware exec and sql variants used
- funlen/cyclop/gocognit/nestif/dupl: oversized or duplicated
  functions split into focused helpers across production and test code
- paralleltest/tparallel/thelper/usetesting/testpackage: tests
  parallelized where safe (global log.Initialize kept in the serial
  phase), helpers marked, t.TempDir adopted, external test packages
  where only exported API is used
- gosec: integer conversions clamped or justified, header timeouts
  added, remaining findings suppressed with per-site justifications
- mnd/goconst/lll/wsl_v5/nlreturn/noinlineerr/errcheck and other
  mechanical findings fixed directly

Remove the deprecated log.LogOptions alias (callers migrated to
log.Options). make check is green.

internal/cli/version.go

@@ -2,6 +2,7 @@ package cli
 
 import (
 	"fmt"
+	"os"
 	"runtime"
 
 	"github.com/spf13/cobra"
@@ -15,21 +16,25 @@ func NewVersionCommand() *cobra.Command {
 		Short: "Print version information",
 		Long:  `Print version, git commit, and build information for vaultik.`,
 		Args:  cobra.NoArgs,
-		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("vaultik %s\n", globals.Version)
-			fmt.Printf("  commit:     %s\n", globals.Commit)
-			fmt.Printf("  build date: %s\n", globals.CommitDate)
-			fmt.Printf("  go:         %s\n", runtime.Version())
-			fmt.Printf("  os/arch:    %s/%s\n", runtime.GOOS, runtime.GOARCH)
-			fmt.Printf("  author:     %s\n", globals.Author)
-			fmt.Printf("  homepage:   %s\n", globals.Homepage)
-			fmt.Printf("  license:    %s\n", globals.License)
+		Run: func(_ *cobra.Command, _ []string) {
+			_, _ = fmt.Fprintf(os.Stdout, "vaultik %s\n", globals.Version)
+			_, _ = fmt.Fprintf(os.Stdout, "  commit:     %s\n", globals.Commit)
+			_, _ = fmt.Fprintf(os.Stdout, "  build date: %s\n", globals.CommitDate)
+			_, _ = fmt.Fprintf(os.Stdout, "  go:         %s\n", runtime.Version())
+			_, _ = fmt.Fprintf(os.Stdout, "  os/arch:    %s/%s\n",
+				runtime.GOOS, runtime.GOARCH)
+			_, _ = fmt.Fprintf(os.Stdout, "  author:     %s\n", globals.Author)
+			_, _ = fmt.Fprintf(os.Stdout, "  homepage:   %s\n", globals.Homepage)
+			_, _ = fmt.Fprintf(os.Stdout, "  license:    %s\n", globals.License)
 
 			if globals.Version == "dev" {
-				fmt.Println()
-				fmt.Println("This is a development build (no version information embedded).")
-				fmt.Println("Build a release binary with 'make vaultik' or download from")
-				fmt.Println("https://sneak.berlin/go/vaultik for embedded version metadata.")
+				_, _ = fmt.Fprintln(os.Stdout)
+				_, _ = fmt.Fprintln(os.Stdout,
+					"This is a development build (no version information embedded).")
+				_, _ = fmt.Fprintln(os.Stdout,
+					"Build a release binary with 'make vaultik' or download from")
+				_, _ = fmt.Fprintln(os.Stdout,
+					"https://sneak.berlin/go/vaultik for embedded version metadata.")
 			}
 		},
 	}