style: apply gofumpt

Estate-wide consolidation pass. The canonical .golangci.yml
(infra ci-templates/golangci.yml, infra#309 pattern) enables the gofumpt
formatter; golangci-lint v2 default set enables NO formatter, which is why
this drift accumulated silently -- the same hole that let two files rot in
dma-cli until they were found by hand (dma-cli#12).

Mechanical and deterministic: `gofumpt -w .`, nothing hand-edited. Verified
per repo before commit -- gofumpt -l now reports 0, gofmt -l reports 0, and
go build + go vet both pass.

Clears this repo to adopt the canonical lint config in a later wave.

internal/web/paste_test.go

@@ -3,9 +3,10 @@ package web
 import (
 	"bytes"
 	"context"
-	"git.d-ma.be/mathias/tapir/internal/adapters/store"
 	"strings"
 	"testing"
+
+	"git.d-ma.be/mathias/tapir/internal/adapters/store"
 )
 
 func TestParseYouTubeVideoID(t *testing.T) {