docs: mark PEND reason end-to-end done (bug-1513), note main_reason follow-up

- aibot_poc_investiagting.md: PEND reason 调查完成 + 转换层补全；新增遗留项（main_reason 恒 0）
- buglog.json: bug-1513 entry
- memory.md: session log

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

.wolf/memory.md

@@ -7398,3 +7398,4 @@
 |------|--------|---------|---------|--------|
 | 02:1x | Added human-readable jobid (job_id_human/human_id) to apiserver responses (backend.FormatJobID reuse); renamed SSE perm event:subscribe->event:view; updated docs (left_scheduler_work, design doc v1.3, cerebrum) | src/frontend/apiserver, src/frontend/schedulerclient, docs | verified live (submit + get_job return 1-0-... form); all tests pass; pushed | ~90k tok |
 | 06:21 | bug-1512 多 worker 过派发修复：handler.c code<0 才 re-PEND；24 作业 8/8/8 全 DONE；单测+提交 e4aaef4 | handler.c test_handlers.c | fixed+verified | ~2k |
+| 09:1x | PEND reason 全链路补全（bug-1513）：controller SETPREASON hook 推送 + apiserver 转换层填充 + JOB_DEFAULT_COLUMN；集群验证 resreq type==nosuchhost → host_reasons [{t1,3},{t2,3},{t3,3}]；提交 ac6131d | apiserver.c convert.go convert_pure.go convert_test.go models/jobs.go | verified | ~40k |