fix: tea CLI login failure handling, error messages, release retry

configure_tea_login silently ignored tea login add/default failures,
causing cryptic "no available login" errors in subsequent tea commands.
Now raises TeaCLIError with stdout/stderr on failure.

TeaCLI._run now includes stdout in error messages (tea writes some
errors like "no available login" to stdout, not stderr).

publish.py retries Gitea release creation up to 3 times with exponential
backoff (2s, 4s) on transient failures. "Already exists" errors are
treated as success (idempotent, no retry).

Root cause: CI run #2822 — post-merge/release-and-maintain failed
creating Gitea release v0.38.1 because tea login add silently failed.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

tests/unit/test_gitea_cli.py

@@ -1,4 +1,4 @@
-"""Unit tests for scripts/gitea_cli.py."""
+"""Unit tests for devx/gitea_cli.py."""
 
 from __future__ import annotations
 
@@ -77,6 +77,25 @@ class TestTeaCLIRun:
             with pytest.raises(TeaCLIError, match="auth error"):
                 cli._run(["labels", "list"])
 
+    def test_run_failure_includes_stdout(self) -> None:
+        """tea writes some errors to stdout (e.g. 'no available login')."""
+        cli = TeaCLI(tea_bin="/fake/tea")
+        mock_result = MagicMock(returncode=1, stdout="no available login", stderr="")
+        with patch("subprocess.run", return_value=mock_result):
+            with pytest.raises(TeaCLIError, match="no available login"):
+                cli._run(["releases", "create"])
+
+    def test_run_failure_includes_both_stdout_and_stderr(self) -> None:
+        """When both stdout and stderr have content, both are included."""
+        cli = TeaCLI(tea_bin="/fake/tea")
+        mock_result = MagicMock(returncode=1, stdout="partial error", stderr="auth error")
+        with patch("subprocess.run", return_value=mock_result):
+            with pytest.raises(TeaCLIError, match="partial error"):
+                cli._run(["labels", "list"])
+            with patch("subprocess.run", return_value=mock_result):
+                with pytest.raises(TeaCLIError, match="auth error"):
+                    cli._run(["labels", "list"])
+
     def test_run_tea_not_found_raises_tea_error(self) -> None:
         cli = TeaCLI(tea_bin="tea")
         with patch("subprocess.run", side_effect=FileNotFoundError("tea not found")):
@@ -380,9 +399,11 @@ class TestConfigureTeaLogin:
     def test_configures_login_when_not_present(self, mock_subprocess: MagicMock, mock_which: MagicMock) -> None:
         """configure_tea_login adds login when not already configured."""
         mock_list = MagicMock(returncode=0, stdout="")
-        mock_subprocess.return_value = mock_list
+        mock_add = MagicMock(returncode=0, stdout="Login successful", stderr="")
+        mock_default = MagicMock(returncode=0, stdout="", stderr="")
+        mock_subprocess.side_effect = [mock_list, mock_add, mock_default]
         configure_tea_login()
-        assert mock_subprocess.call_count >= 2  # login list + login add + login default
+        assert mock_subprocess.call_count == 3  # login list + login add + login default
 
     @patch.dict("os.environ", {"CI_GITEA_TOKEN": "tok"})
     @patch("devx.gitea_cli.shutil.which", return_value="/usr/bin/tea")
@@ -393,3 +414,37 @@ class TestConfigureTeaLogin:
         mock_subprocess.return_value = mock_list
         configure_tea_login()
         assert mock_subprocess.call_count == 1  # only login list, no add
+
+    @patch.dict("os.environ", {"CI_GITEA_TOKEN": "tok"})
+    @patch("devx.gitea_cli.shutil.which", return_value="/usr/bin/tea")
+    @patch("devx.gitea_cli.subprocess.run")
+    def test_raises_on_login_add_failure(self, mock_subprocess: MagicMock, mock_which: MagicMock) -> None:
+        """configure_tea_login raises TeaCLIError if tea login add fails."""
+        mock_list = MagicMock(returncode=0, stdout="")
+        mock_add = MagicMock(returncode=1, stdout="", stderr="invalid token")
+        mock_subprocess.side_effect = [mock_list, mock_add]
+        with pytest.raises(TeaCLIError, match="login add failed"):
+            configure_tea_login()
+
+    @patch.dict("os.environ", {"CI_GITEA_TOKEN": "tok"})
+    @patch("devx.gitea_cli.shutil.which", return_value="/usr/bin/tea")
+    @patch("devx.gitea_cli.subprocess.run")
+    def test_raises_on_login_default_failure(self, mock_subprocess: MagicMock, mock_which: MagicMock) -> None:
+        """configure_tea_login raises TeaCLIError if tea login default fails."""
+        mock_list = MagicMock(returncode=0, stdout="")
+        mock_add = MagicMock(returncode=0, stdout="Login successful", stderr="")
+        mock_default = MagicMock(returncode=1, stdout="", stderr="login not found")
+        mock_subprocess.side_effect = [mock_list, mock_add, mock_default]
+        with pytest.raises(TeaCLIError, match="login default failed"):
+            configure_tea_login()
+
+    @patch.dict("os.environ", {"CI_GITEA_TOKEN": "tok"})
+    @patch("devx.gitea_cli.shutil.which", return_value="/usr/bin/tea")
+    @patch("devx.gitea_cli.subprocess.run")
+    def test_login_add_failure_includes_stdout(self, mock_subprocess: MagicMock, mock_which: MagicMock) -> None:
+        """Error message includes stdout when tea writes errors there."""
+        mock_list = MagicMock(returncode=0, stdout="")
+        mock_add = MagicMock(returncode=1, stdout="Error: invalid username", stderr="")
+        mock_subprocess.side_effect = [mock_list, mock_add]
+        with pytest.raises(TeaCLIError, match="invalid username"):
+            configure_tea_login()