### Fixed

- Label removal on Forgejo is a full-set `PUT`, not a per-label `DELETE`. The
  workflow token gets HTTP 500 on every `DELETE .../labels/{id}` on this
  instance, so the state machine could only ever ADD labels (#192).

- Every `state:*` transition that needs the previous state cleared, and every
  `blocker:*` that should lift, can now actually clear. They were inert (#192).

- A label edit that fails is fatal to `labels-reconcile`, matching
  `issueflow-reconcile`. One cause had two contradictory policies (#192).

- A failed write reaches the sweep's exit code: per-PR tolerance is kept for
  READS, but a sweep that could not write exits non-zero and its output carries
  no `reconciled.` token at all (#192).

- Every label mutation goes through one checked helper, so clearing
  `merge-next` or either `stale` edit fails the sweep too — not only the
  primary state edit (#192).

- A preserved label keeps the id the issue payload already carried, so
  preservation does not depend on a repository-wide list that has nothing to do
  with the issue (#192).

- A removal that changes nothing writes nothing, rather than replacing the set
  with itself and opening a race for no state change (#192).

- Every failure diagnostic on the forgejo backend names the verb as well as the
  path and the status. A read used to say `HTTP 500 from 'repos/…'`, which
  cannot be told from a failed write of the same path (#192).

- The diagnostic names what was attempted and that it did not happen, instead
  of blaming a missing label and telling the operator to bootstrap — a cause it
  had not established (#192, #101).

- An add-label the repo does not carry refuses before any write, so a
  replacement `PUT` can never drop a label nobody asked to remove (#192).

### Added

- `test/forge-backends.test.sh` pins the replacement contract: preserve
  unrelated labels across a combined add+remove, an absent removal as a
  successful no-op, the empty set as a full clear, and `forge_labels_add`
  still `POST`-only, per ceremony#128 (#192).

- `test/labels-reconcile.test.sh` drives a failing write through `main()` — the
  swallow was in the loop, where a fixture-level probe cannot reach (#192).