Final completeness by time window: ranges keep their posting span, release_final() over blocks of done ranges

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

commands/coordinator_run.ts

@@ -5,6 +5,7 @@ import { Prefetcher } from '#services/prefetcher'
 import Planner from '#services/planner'
 import FragmentMerger from '#services/fragment_merger'
 import Settler from '#services/settler'
+import RangeBlocks from '#services/range_blocks'
 import NntpPool from '#services/nntp_pool'
 import coordinatorConfig from '#config/coordinator'
 
@@ -13,6 +14,8 @@ const PLAN_EVERY_MS = 60 * 60 * 1000
 const MERGE_EVERY_MS = 60 * 1000
 const MERGE_BUDGET_MS = 30 * 1000
 const STOP_WAIT_MS = 15 * 1000
+/** range_blocks (release_final) after ranges finish. */
+const BLOCKS_EVERY_MS = 5 * 60 * 1000
 
 /**
  * The coordinator's background work (REBUILD.md, part 1): the prefetcher,
@@ -60,8 +63,13 @@ export default class CoordinatorRun extends BaseCommand {
     let plannedAt = 0
     let tailedAt = 0
     let mergedAt = 0
+    let blocksAt = 0
     while (!stopping) {
       try {
+        if (main && Date.now() - blocksAt >= BLOCKS_EVERY_MS) {
+          blocksAt = Date.now()
+          await RangeBlocks.rebuild()
+        }
         if (main && Date.now() - plannedAt >= PLAN_EVERY_MS) {
           plannedAt = Date.now()
           const { groups, ranges } = await Planner.planAll()