style: apply gofmt across Go sources

Repo-wide gofmt sweep: const-block alignment, doc-comment spacing,
statement-after-brace fix in media.go, trailing blank lines. No
semantic changes — whitespace-insensitive diff is empty for every
file in this commit.

internal/sync/cfi_verify.go

@@ -167,12 +167,12 @@ func bookCharOffset(conv *CFIConverter, spineIndex int, node *html.Node, runeOff
 // standard CFI: the anchor block's cssSelector, the character offset
 // within that block's text, and the spine document's href.
 type ProgressAnchor struct {
-	CSSSelector    string
-	CharOffset     int
-	Href           string
-	HealedCFI      string
-	Healed         bool
-	HealedPct      *float64
+	CSSSelector string
+	CharOffset  int
+	Href        string
+	HealedCFI   string
+	Healed      bool
+	HealedPct   *float64
 }
 
 // VerifyProgressAnchor resolves a client-submitted standard CFI against