fix(work-item): assign issues via PATCH instead of broken sub-route

`tea --add-assignees` posts to /issues/{n}/assignees, which returns 404 on
this Forgejo deployment and makes every `claim` fail. Set the assignee through
the issue PATCH endpoint (full assignees list), which the server accepts, and
reuse `edit_labels` for the status transition. Update the CLI e2e fake `tea`
to model the PATCH assignee call.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WMctdE9E1c8d6UHQWX8rNt

work_item/src/work_item/core.py

@@ -446,19 +446,24 @@ class Gitea:
         self.tea(*args)
 
     def claim(self, story: Story) -> None:
-        self.tea(
-            "issues",
-            "edit",
-            str(story.number),
-            "--repo",
-            self.config.repo_slug,
-            "--add-assignees",
-            self.config.assignee,
-            "--add-labels",
-            "status/in-progress",
-            "--remove-labels",
-            "status/backlog,status/ready,status/blocked,status/review,status/done",
+        self.edit_labels(
+            story.number,
+            add=("status/in-progress",),
+            remove=(
+                "status/backlog",
+                "status/ready",
+                "status/blocked",
+                "status/review",
+                "status/done",
+            ),
         )
+        self.set_assignee(story.number, self.config.assignee)
+
+    def set_assignee(self, issue: int, assignee: str) -> None:
+        # Some Gitea/Forgejo deployments 404 on the issues/{n}/assignees
+        # sub-route that `tea --add-assignees` uses; the issue PATCH endpoint
+        # accepts the full assignees list and works across those versions.
+        self.api(f"{self.base}/issues/{issue}", method="PATCH", data={"assignees": [assignee]})
 
     def comment(self, issue: int, body: str) -> None:
         self.tea("comments", "add", str(issue), body, "--repo", self.config.repo_slug)

work_item/tests/test_cli_e2e.py

@@ -50,6 +50,13 @@ if args[0] == "api":
         out(state["prs"][str(number)])
     elif "/commits/" in endpoint and endpoint.endswith("/status"):
         out({"state": state.get("ci_state", "success")})
+    elif "--method" in args and args[args.index("--method") + 1] == "PATCH" and "/issues/" in endpoint:
+        number = int(endpoint.rsplit("/", 1)[1])
+        issue = next(x for x in state["issues"] if x["number"] == number)
+        payload = json.loads(args[args.index("--data") + 1])
+        if "assignees" in payload:
+            issue["assignees"] = [{"login": login} for login in payload["assignees"]]
+        save(); out(issue)
     else:
         raise SystemExit(f"unsupported api: {endpoint}")
 elif args[:2] == ["issues", "edit"]: