Rebuild: the live tail

coordinator:run plans the articles after each group's last range every
TAIL_EVERY_SECONDS (120): one LIST ACTIVE per name prefix gives every
group's newest article, and new articles become ranges at priority -1,
leased and prefetched before any history. A group gets a tail range once
it has TAIL_MIN_ARTICLES (100k, a chunk) new or its last planning is
TAIL_MAX_DELAY_MINUTES (15) ago, so quiet groups don't make a range every
round. History (planAll, hourly) is now only for groups not planned yet.
ranges:plan --tail plans one round.

Found on the way: with XFEATURE COMPRESS GZIP on, Eweka compresses LIST
ACTIVE's reply too ("215 NewsGroups Follow [COMPRESS=GZIP]"), and
listActive waited for a plain end that never came (groups:add --top too).
It reads the compressed reply now; the fake server in the test does both.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/unit/nntp/xover_client.spec.ts

@@ -39,6 +39,16 @@ function server(): Promise<{ port: number; close: () => void }> {
               sock.write('224 Overview Information Follows\r\n')
               send(Buffer.concat([body, Buffer.from('.\r\n')]))
             }
+          } else if (line.startsWith('LIST ACTIVE')) {
+            // As Eweka: compressed too once XFEATURE COMPRESS GZIP is on.
+            const body = Buffer.from('a.b.test 102 101 y\r\na.b.other 9000000000 2 y\r\n')
+            if (gzip) {
+              sock.write('215 NewsGroups Follow [COMPRESS=GZIP]\r\n')
+              send(Buffer.concat([deflateSync(body), Buffer.from('.\r\n')]))
+            } else {
+              sock.write('215 NewsGroups Follow\r\n')
+              send(Buffer.concat([body, Buffer.from('.\r\n')]))
+            }
           } else if (line === 'QUIT') sock.end('205 bye\r\n')
         }
       })
@@ -68,6 +78,10 @@ test.group('nntp / XoverClient', () => {
         assert.equal(overviews[1][1].subject, 'Show.S01E01 - "a.mkv" yEnc (2/2)')
         assert.deepEqual(await client.xover(1, 1), [])
         assert.lengthOf(await client.xover(101, 102), 2)
+        assert.deepEqual(await client.listActive('a.b.*'), [
+          { name: 'a.b.test', high: 102, low: 101 },
+          { name: 'a.b.other', high: 9_000_000_000, low: 2 },
+        ])
       } finally {
         client.close()
         close()