Tighten lnw comments and log form after review (#87)

Cross-reference lnwChapterRe from the function doc instead of restating
its rationale, drop the redundant '; skipping' from the fail-closed log
to match the package's bare verb:detail form, and reword the truncation
comment so the logged body length is not described as a code-made
distinction.

backend/internal/latest/sites.go

@@ -98,11 +98,7 @@ const lnwCommentMarker = "wpd-threads"
 // such guarantee — demonicChapterRe matches any chaptered.php?manga=<id> anchor
 // with no per-series scoping, because the stored series_id for demonic is a
 // slug, not the numeric id the URL carries, so it cannot easily be scoped.
-// lightnovelworld is unscoped for a stronger reason: its chapter addresses
-// carry the Chapter Slug, which is not the Series identity, so no stored-slug
-// pattern can cover a Series' whole list (see lnwChapterRe). Instead of
-// scoping, its branch scans only the body before the comment thread marker and
-// skips the page when the marker is absent.
+// lightnovelworld is unscoped and body-truncated instead — see lnwChapterRe.
 func latestChapterFrom(site, seriesURL, body string) (latestChapter, bool) {
 	var re *regexp.Regexp
 	switch site {
@@ -151,11 +147,11 @@ func latestChapterFrom(site, seriesURL, body string) (latestChapter, bool) {
 		// page any visitor can write to, so the scan never reads past it (see
 		// lnwChapterRe). A body without the marker is skipped, never scanned
 		// whole — a redesign must degrade into staleness, not into a wrong
-		// shared value. The body length distinguishes a genuine markup change
-		// from a body the size cap cut short.
+		// shared value; the logged body length tells a markup change from a
+		// body the size cap cut short.
 		i := strings.Index(body, lnwCommentMarker)
 		if i < 0 {
-			log.Printf("latest poll %q: no %s marker in %d bytes; skipping", seriesURL, lnwCommentMarker, len(body))
+			log.Printf("latest poll %q: no %s marker in %d bytes", seriesURL, lnwCommentMarker, len(body))
 			return latestChapter{}, false
 		}
 		body = body[:i]

backend/internal/latest/sites_test.go

@@ -414,8 +414,8 @@ func TestLatestChapterFrom(t *testing.T) {
 		// Stored before the slug split, so the address carries the ...-not
 		// Chapter Slug; the 100-423 block under the other slug must still win.
 		// The body is the chapter-list portion of lnwSeriesFixture with the
-		// comment block omitted (that is the next case's job); the marker is
-		// kept, because a body without it is skipped, not scanned.
+		// comment block omitted; the marker is kept, because a body without it
+		// is skipped, not scanned.
 		{
 			name:      "lightnovelworld max spans both chapter slugs",
 			site:      "lightnovelworld",