fix(core,fuse,cli): harden writes, trash and cleanup found by account acceptance runs

The FUSE acceptance suite now runs on the signed-in account by default and
cleans up after itself; its first live runs found three daemon bugs.

- B101: a pwrite past EOF now authors the hole it leaves, so truncated bytes
  no longer come back from the base. A write attached to a create while that
  create uploads becomes a revision of the real uid instead of being dropped.
- B102: removing a folder drops the queued revisions of files below it, found
  through the node tree, with their blobs and in-flight uploads. `pdfs rm`
  now drops queued ops too.
- B103: each server call of a trash refresh times out after 120 s, so one hung
  call can no longer freeze the trash listing until restart.

Acceptance suite: account mode with a manifest, lock and reaper; cleanup by
uid; queued ops naming a test root count as leftovers; new edge-case,
throughput and B100/B101 cases; the wide-directory case is split from the
deep tree and gets a doubled budget. Adds `pdfs trash --json`.

docs/CLI.md

@@ -177,7 +177,7 @@ commands are for scripts and for cases where the mount is not available.
 ## Scripting with `--json`
 
 The global `--json` flag makes query commands print JSON: `status`, `ls`, `pins`, `sync list`,
-`devices list`, `locations`, `transfers`, `activity` and `cache inspect`. Commands that change
+`devices list`, `locations`, `transfers`, `activity`, `trash` and `cache inspect`. Commands that change
 something keep their human-readable output; check their exit code.
 
 ```bash