fix(fuse): end a mirror pass at the stop (B169)

A stop that came while a mirror pass was uploading let the pass go on to
the next level of folders until the stop gave up on it and the runtime's
end cancelled the uploads under it. Once the daemon is stopping, a batch
starts none of its waiting ops, lets the ones sending finish, and ends
the pass; the remote walk and a new pass stop too.

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 B168.
+- Fixes from the simulation and account runs since then: B127 and B141 to B169.
 - **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`.
 
@@ -109,7 +109,8 @@ Tracks `docs/MILESTONE-3.0.0.md`. Update it with every commit that moves a phase
          running, which the run's queue wait takes for an empty queue (the script's side).
          Looking into it found the start spending 1.7 s rebuilding listings (B167, fixed).
          Its journal check caught a file removed with its folder while uploading being
-         sent again, to the root (B168, fixed).
+         sent again, to the root (B168, fixed), and a stop that let a mirror pass go on
+         until the runtime ended under it (B169, fixed).
 5. **Release**: 2.10.0 is tagged; the 2.9.0 tag still waits for the user's go-ahead.
 
 ## After 3.0.0