docs(ISSUE-WP-0006): Forgejo-only language and projection boundary

Prefer Forgejo as the self-hosted forge product. Keep Gitea only as the
Gitea-compatible API identifier (module backends/gitea, type string
gitea). FORGEJO_TOKEN is preferred; GITEA_* remains a deprecated alias.

INTENT/SCOPE quote ACT-ADR-005: issue-core is not the fleet ops claim
queue. Connector docs describe repo work record → hub index → optional
Forgejo projection, not activity-core → issue-core → harness.

Assistant: grok
Assistant-Session: 01a09dc6-3f0d-7c93-8b11-8e83c0623d49

tests/test_cli_commands.py

@@ -53,7 +53,7 @@ class TestCLICommands:
             ], input='https://git.example.com\ntestorg\ntestrepo\n')
 
         assert result.exit_code == 0
-        assert 'Using API token from GITEA_API_TOKEN environment variable' in result.output
+        assert 'Using API token from FORGEJO_TOKEN environment variable' in result.output
         assert 'Backend \'test-gitea\' added successfully' in result.output
 
         # Verify save_backend_configs was called with correct data
@@ -205,8 +205,13 @@ class TestEnvironmentTokenDetection:
 
     @patch('os.getenv')
     def test_gitea_token_detection(self, mock_getenv):
-        """Test GITEA_API_TOKEN environment variable detection."""
-        mock_getenv.return_value = 'test-env-token'
+        """Deprecated GITEA_API_TOKEN alias is still accepted."""
+        def _getenv(name, default=None):
+            if name == 'GITEA_API_TOKEN':
+                return 'test-env-token'
+            return default
+
+        mock_getenv.side_effect = _getenv
 
         from issue_core.cli.backend_commands import add_backend
 
@@ -220,4 +225,5 @@ class TestEnvironmentTokenDetection:
                     ], input='https://git.example.com\ntestorg\ntestrepo\n')
 
         assert result.exit_code == 0
-        assert 'Using API token from GITEA_API_TOKEN environment variable' in result.output
+        assert 'Using API token from GITEA_API_TOKEN' in result.output
+        assert 'deprecated alias; prefer FORGEJO_TOKEN' in result.output