hive-forge: warn when --tail saturates the pagination cap (argus 🟡 on #770)

hive-forge/src/verbs/comments.rs

@@ -92,12 +92,29 @@ fn fetch_head(client: &Client, repo: &str, number: u64, limit: u64) -> Result<Ve
 /// items in chronological order. Forgejo orders
 /// `/issues/<n>/comments` oldest-first so the trailing slice maps
 /// directly to "most recent N".
+///
+/// When the fetch saturates `TAIL_MAX_PAGES` (i.e. all 20 pages came
+/// back full at 50/page) we can't tell whether more comments exist
+/// upstream. Surface a stderr warning so the caller knows the
+/// "tail" is anchored to the first 1000 comments, not necessarily
+/// the actual newest of the thread. False positive: a thread with
+/// EXACTLY 1000 comments will warn even though the slice IS the
+/// real tail — acceptable noise given how rare 1000-comment threads
+/// are (closes argus 🟡 on PR #770).
 fn fetch_tail(client: &Client, repo: &str, number: u64, n: usize) -> Result<Vec<Value>> {
     let all = client.get_json_all(
         &format!("/repos/{repo}/issues/{number}/comments?limit=50"),
         TAIL_MAX_PAGES,
     )?;
     let total = all.len();
+    if total >= TAIL_MAX_PAGES as usize * 50 {
+        eprintln!(
+            "warning: hit pagination cap ({TAIL_MAX_PAGES} pages × 50 = \
+             {total} comments); --tail slice is anchored to the first \
+             {total} comments and may not include the actual newest of \
+             the thread."
+        );
+    }
     if total <= n {
         return Ok(all);
     }