fix(config): Restore rediraffe_redirects default dropped in workspace refactor

why: The {} default was intentional, not a regression. The test name
says "redirects_are_opt_in" — smoke tests build in a temp dir with
no redirects.txt, so "redirects.txt" as default triggers a rediraffe
warning that -W makes fatal. docs/conf.py already explicitly opts in.
what:
- Revert rediraffe_redirects back to {} (opt-in by default)
- Restore original test name and assertion

Author: tony

packages/gp-sphinx/src/gp_sphinx/config.py

@@ -408,7 +408,7 @@ def merge_sphinx_config(
             DEFAULT_COPYBUTTON_LINE_CONTINUATION_CHARACTER
         ),
         # Rediraffe
-        "rediraffe_redirects": "redirects.txt",
+        "rediraffe_redirects": {},
         "rediraffe_branch": "master~1",
         # Warnings
         "suppress_warnings": list(DEFAULT_SUPPRESS_WARNINGS),

tests/test_config.py

@@ -385,14 +385,14 @@ def test_merge_sphinx_config_html_paths() -> None:
     assert "html_extra_path" not in result
 
 
-def test_merge_sphinx_config_redirects_default() -> None:
-    """Redirect generation defaults to redirects.txt file path."""
+def test_merge_sphinx_config_redirects_are_opt_in() -> None:
+    """Redirect generation defaults stay quiet for minimal consumers."""
     result = merge_sphinx_config(
         project="test",
         version="1.0",
         copyright="2026",
     )
-    assert result["rediraffe_redirects"] == "redirects.txt"
+    assert result["rediraffe_redirects"] == {}
 
 
 def test_make_linkcode_resolve_preserves_package_dir() -> None: