test(ha-config-bootstrap): RED-phase tests for ha-term.bin durability (task 6.1)

5 Unity tests covering persist (req 9.1), restore (req 9.2 RED),
missing-file zero-init (req 9.3), CRC-mismatch safe-zero, and
write+rename atomicity. Build fails with 3 undefined-reference linker
errors on ha_restore_term() — expected RED phase proof.

src/controller/meson.build

@@ -105,6 +105,7 @@ controller_unit_test_src = [
   'testsuite/test_ha_election.c',
   'testsuite/test_ha_bootstrap.c',
   'testsuite/test_ha_bootstrap_support.c',
+  'testsuite/test_ha_durability.c',
   'startup_validation.c',
   'worker.c',
   'persist.c',