fix(fuse): list again when a listing changed while it was published (B159)

A lookup in the root publishes the "Shared with me" entry only if the root
listing did not change while its plan was read, and answered EAGAIN when it
had. Right after a restart the root is listed again as the first lookups come
in, so a write could fail with "Resource temporarily unavailable".
ensure_children now takes the listing again, up to four times.

docs/MILESTONE-3.0.0-STATUS.md

@@ -9,7 +9,7 @@ Tracks `docs/MILESTONE-3.0.0.md`. Update it with every commit that moves a phase
 - **Phase 2**: local ids, inode = local id, one tree for every mount (2.10.0).
 - **Phase 3, first part**: mkdir, create, rename, unlink and rmdir on the mount are recorded
   locally and sent from the queue; `"local_first": false` brings back the old path (5e0f30c).
-- Fixes from the simulation and account runs since then: B127 and B141 to B158.
+- Fixes from the simulation and account runs since then: B127 and B141 to B159.
 - **Sync issues, first cut** (§6.2): refusals sorted into issues, shown at once in the app,
   tray and CLI; Export button and `pdfs sync export`; `pdfs sync issues`.
 
@@ -82,7 +82,9 @@ Tracks `docs/MILESTONE-3.0.0.md`. Update it with every commit that moves a phase
          again after its create lost its answer (B156, fixed). With sixteen drain workers
          (16fca10), seed 4 failed every replay on a write after an upload that was not read
          back (B157, fixed). Seed 3 then failed four of ten runs on two renames of one file
-         landing out of order (B158, fixed).
+         landing out of order (B158, fixed). Flaky-link seed 4 failed one of ten runs on a
+         lookup that answered `EAGAIN` while the root was listed again after a restart (B159,
+         fixed).
    - [ ] Known-bug list in `sim/run.rs` is empty: B125 and B130 open; B127, B129 and B132 fixed
          but unconfirmed.
    - [ ] A clean account run. The one on a6f36d5 (2026-10-04, LAN: 427 passed, 12 failed)