feat: reserve queue capacity for recent models

modelhub_submmit_api/README.md

@@ -120,6 +120,12 @@ bash run_poll.sh --dry-run
   memory rule as new submissions. Only tasks whose own repository size times `1.20` exceeds
   their selected GPU capacity are stopped, after a fresh account-scoped active-state check.
   Incomplete size/capacity evidence is never used for cancellation.
+- Models older than seven days may occupy only positions 1–80 of each account's active queue.
+  The account pool enforces the boundary atomically. Once all accounts reach 80, discovery no
+  longer expands beyond seven days. Cleanup stops OOM tasks first, recalculates the surviving
+  queue order, and on startup stops old tasks still ranked 81 or later. Scheduled cleanup then
+  retains positions 81–95 and stops only old tasks ranked 96 or later. Recent overflow tasks stay.
+  Unknown ModelScope timestamps never authorize a cancellation.
 
 ## Important Flags
 
@@ -153,7 +159,12 @@ Common flags:
 - `--submit-concurrency`: concurrent task submission calls used by each cycle (0 = auto)
 - `--post-cycle-cooldown-seconds`: pause after a successful cycle before next cycle (default 2)
 - `--max-cycles`: optional hard stop for testing or batch windows
-- `--disable-queue-cleanup`: disable automatic deterministic OOM cleanup
+- `--disable-queue-cleanup`: disable automatic OOM and old-overflow queue cleanup
+
+The first automatic cleanup removes models older than seven days after each
+account's position 80. Later scheduled cleanups use position 95, while admission
+continues to reserve positions 81-100 for recent models. Override the later
+threshold with `MODELHUB_DYNAMIC_OLD_MODEL_CLEANUP_THRESHOLD`.
 
 Failure-informed preflight is enabled by default. It rejects deterministic
 missing-file and predicted-OOM cases, clamps unsafe context-length arguments,