style: apply gofmt

Estate-wide consolidation pass. golangci-lint v2 default set enables NO
formatter, so gofmt drift accumulated silently across the estate -- 8 repos
were carrying it, this one included. Same hole that let two files rot in
dma-cli until they were found by hand (dma-cli#12).

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

Clears this repo to adopt the canonical .golangci.yml (infra
ci-templates/golangci.yml, infra#309 pattern) in a later wave.

ingestion/internal/audit/buffer.go

@@ -28,8 +28,8 @@ type FileBuffer struct {
 }
 
 type bufferLine struct {
-	ID    string              `json:"id"`
-	Entry capture.AuditEntry  `json:"entry"`
+	ID    string             `json:"id"`
+	Entry capture.AuditEntry `json:"entry"`
 }
 
 // NewFileBuffer returns a buffer backed by path. The parent directory is