test: remove the Bash suite

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

tests/sabotage.py

@@ -1,6 +1,6 @@
 """Self test of the suite: prove that it goes red when the backup is broken.
 
-Ported from `test/run.sh --sabotage`. Run with `task test:sabotage`.
+Run with `task test:sabotage`.
 
 A throwaway copy of the tree gets a backup.sh whose `restic backup` call is a no-op, the
 nastiest kind of regression (the script still reports success). The compat tests run

tests/test_compat.py

@@ -1,4 +1,4 @@
-"""Backwards-compatibility suite, ported from test/compat.sh.
+"""Backwards-compatibility suite.
 
 Everything here describes behaviour the image has today and that users depend on.
 A change that turns one of these red is a breaking change, whether or not intended.

tests/test_features.py

@@ -1,4 +1,4 @@
-"""Feature-gated tests, ported from test/features.sh.
+"""Feature-gated tests.
 
 Each class is guarded by `@pytest.mark.feature(<gate>)`: it runs as soon as the built
 image ships the feature (detected in conftest.py) and is skipped before that. A gate