Rebuild: post a batch early when 100k files wait; log failing stats refreshes

A picture group's 500k articles made batches over the server's 256 MB
body limit: HTTP 413, the range given back and leased again in a loop
(148597: 39 times in 30 minutes). The worker now also posts once
100,000 completed or edge-cut files wait (RangeIndexer.pending).
A stats refresh that failed kept the previous totals silently; it
logs the error now.

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

commands/edge_node.ts

@@ -8,6 +8,8 @@ import { gzip, unzip } from 'node:zlib'
 import { RangeIndexer, decodeFrames, isKeepalive, throttle, toWire, type EdgeBatch, type Lease } from '#lib/edge/index'
 
 const IDLE_MS = 30_000
+/** A batch is posted once this many files (completed, or cut at an edge) wait, whatever its articles. */
+const MAX_PENDING_FILES = 100_000
 const unzipAsync = promisify(unzip)
 const gzipAsync = promisify(gzip)
 const RETRIES = 8
@@ -166,7 +168,8 @@ export default class EdgeNode extends BaseCommand {
       indexer.addText(text.toString('utf8'), chunk.to + 1)
       reachedEnd = chunk.to >= range.end
       if (reachedEnd) indexer.finish()
-      if (reachedEnd || chunk.to + 1 - batchFrom >= this.batchArticles) {
+      // Also early when many files wait: a picture group's 500k articles made batches over the server's 256 MB limit (HTTP 413).
+      if (reachedEnd || chunk.to + 1 - batchFrom >= this.batchArticles || indexer.pending >= MAX_PENDING_FILES) {
         post(indexer.take())
         batchFrom = chunk.to + 1
       }