fix(regression): correct SHAs for bad-backup/bad-restore (A-reg-3) + consume inbox

Both compose.yml uploads had empty files due to a bash encoding bug.
Fixed via Python API upload; new SHAs:
- regression-bad-backup: cd52b3a (backupbot.backup.path=/nonexistent-path-cc-ci-canary-bad)
- regression-bad-restore: 7e03499 (backup targets .backup-data subdir + command creates it)

Adversary confirmed bad-install ✓ and bad-upgrade ✓ from run artifacts.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/regression/test_canaries.py

@@ -128,7 +128,7 @@ _BAD_BACKUP = {
     "src": "recipe-maintainers/custom-html",
     # Pin: regression-bad-backup @ 2026-06-02 — backupbot.backup.path=/nonexistent-path-cc-ci-canary-bad
     # `abra app backup create` fails → backup tier RED. install+upgrade still PASS.
-    "ref": "e1e3c5fc5e2bd414600b6d3a9f2266566415ff34",
+    "ref": "cd52b3a02d2cc1a73ec598766cc1bf1c62b465ec",
     "expected_green": False,
     "stages": "install,upgrade,backup",
     "failing_tier": "backup",
@@ -144,7 +144,7 @@ _BAD_RESTORE = {
     # Pin: regression-bad-restore @ 2026-06-02 — backup captures /usr/share/nginx/html/.backup-data/
     # (a subdir NOT containing ci-marker.txt). Restore restores the subdir → marker stays "mutated"
     # → test_restore_returns_state FAILS → restore tier RED. install+upgrade+backup PASS.
-    "ref": "5a481cc1f6b2a46279b8e0eca09ca7cb4dc6f25d",
+    "ref": "7e03499ff17b343b622b510efcfc44add9651065",
     "expected_green": False,
     "stages": "install,upgrade,backup,restore,custom",
     "failing_tier": "restore",