feat(fuse,core): record namespace changes locally and send them from the queue

A new folder, a new file, a rename or a delete through the mount no longer
waits for Drive: it is recorded locally, the call returns at once, and the
drain sends it as it does offline. `"local_first": false` in config.json
brings back the old path for this release.

Fixes found by the simulation runs on the way:
- B129: a file deleted while its first upload is on the wire is trashed once
  the upload lands.
- B132, B140: files made in a new folder survive a restart; a landed folder
  hands its queued children over in the stored node too.
- B138: a create waits for the rename or trash that frees its name.
- B139: a file closed while its first upload lands keeps its last write.
- B141: a rename a worker holds stays queued, and the newer one waits behind
  it instead of racing it.
- B142: a rename of a file whose create lands meanwhile goes to the uid Drive
  gave it instead of answering EBUSY.
- B143: a create whose read-back fails as the link drops is adopted before
  the next op for it is sent, so its next write is not a conflict copy.

docs/CONFIGURATION.md

@@ -80,6 +80,7 @@ fix it.
 | `ignore_patterns` | list | see below | — | Global ignore rules for synced folders |
 | `device_uid` | string | none | Computers → Continue This Backup Here… | The computer this machine continues. Unset means "match by hostname" |
 | `conflict_sweep` | `off` / `report` / `enforce` | `report` | — | See [`conflict_sweep`](#conflict_sweep) |
+| `local_first` | bool | `true` | — | See [`local_first`](#local_first) |
 | `language` | gettext code | system | General → Appearance | Language of the app, tray and prompt, such as `de` or `pt_BR` |
 | `proton_theme` | bool | follow system | General → Appearance | Proton's colours instead of the system theme |
 | `online_map` | bool | `false` | General → Appearance | Street map for Places from OpenFreeMap |
@@ -116,6 +117,15 @@ were copied from.
 
 `PDFS_CONFLICT_SWEEP` overrides the setting for one run of the service.
 
+### `local_first`
+
+A new folder, a new file, a rename or a delete made through the mount is recorded locally and the
+call returns at once. The change goes to Drive from the queue, the same way it does offline, and
+`pdfs status` counts it until it lands.
+
+Set it to `false` to have these calls wait for Drive again, as before 3.0.0. The switch is there
+for one release, in case the queued path misbehaves for you; please report it if it does.
+
 ### `open_with`
 
 Decides how files picked in the search launcher or the app are opened. Rules are tried in order;