v0.3.4: one implementation of apply/revert (patch/mw_patch.py)

The "strip the TRUECLOUD_PATCH block" logic existed twice -- in apply.sh's heredoc
and in an inline heredoc in uninstall.sh -- and the uninstall copy was the untested
one. That is precisely how the two could have drifted apart, with apply.sh
reverting one set of files and uninstall.sh another.

Both now call patch/mw_patch.py. 17 new tests cover it, including that
revert_nested never touches restic.py: that file carries a TRUECLOUD_PATCH block
too, but it belongs to the providers module, and removing it would silently break
B2 backups.

apply.sh imports it fail-safe -- on ImportError the backend patch is skipped and
middlewared starts stock, which is this script's whole design principle. The
import uses sys.path.append, never insert(0): prepending would give patch/
precedence over the stdlib for that interpreter, so a future patch/json.py would
shadow the real json module and break the boot.

Also: the README's create_task.py example still taught `--password <secret>`, which
is how a security fix quietly fails to land. It now shows --password-stdin.

132 tests, ruff and shellcheck clean.

CHANGELOG.md

@@ -1,5 +1,29 @@
 # Changelog
 
+## v0.3.4 — 2026-07-13
+
+### Changed
+
+- **One implementation of apply/revert (`patch/mw_patch.py`).** The "strip the
+  `TRUECLOUD_PATCH` block" logic existed twice — in `apply.sh`'s heredoc and in an
+  inline heredoc in `uninstall.sh` — and the uninstall copy was the untested one.
+  That is exactly how the two could have drifted apart, with `apply.sh` reverting
+  one set of files and `uninstall.sh` another. Both now call the same tested
+  module (17 new tests, including that `revert_nested` never touches `restic.py`,
+  which belongs to the providers module and whose removal would silently break B2
+  backups).
+
+  `apply.sh` imports it fail-safe: if it cannot, the backend patch is skipped and
+  middlewared starts stock, which is this script's whole design principle. The
+  import uses `sys.path.append`, never `insert(0)` — prepending would give
+  `patch/` precedence over the stdlib for that interpreter, so a future
+  `patch/json.py` would shadow the real `json` and break the boot.
+
+### Docs
+
+- The README's `create_task.py` example still taught `--password <secret>`, which
+  is how a security fix quietly fails to land. It now shows `--password-stdin`.
+
 ## v0.3.3 — 2026-07-13
 
 ### Security