fix(regression): fix relative import (A-reg-1) + consume inbox

- tests/regression/test_canaries.py: replace `from .conftest import ...`
  (relative import fails when not a package) with sys.path + direct import,
  matching the pattern used by all other tests in this repo.
- Delete machine-docs/BUILDER-INBOX.md (Adversary inbox consumed).
- Update STATUS-regression.md + JOURNAL-regression.md with first two
  canary run results (bad-false-green RED confirmed, good-simple GREEN confirmed).

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

machine-docs/JOURNAL-regression.md

@@ -51,6 +51,26 @@ lasuite-docs is slow (10-20 min) so will run it last.
 
 ---
 
-## Step 1 — initial canary runs (in progress, 2026-06-02)
+## Step 1 — initial canary runs (2026-06-02 ~01:28-01:40Z)
 
-Committed suite, will record canary outputs here as they complete.
+### bad-false-green run (regression-bad-canary-1)
+Command: `RECIPE=custom-html REF=71e7326a... SRC=recipe-maintainers/custom-html cc-ci-run runner/run_recipe_ci.py`
+Result: RC=1, custom=FAIL
+Key output:
+- `test_content_type_html_and_txt` FAILED: `ccci-89273b0b.txt Content-Type='application/octet-stream'`, expected `text/plain`
+- All other tiers (install/upgrade/backup/restore): PASS
+- `flags: {clean_teardown: True, no_secret_leak: True}`
+- Confirms: regression test `assert rc != 0` will PASS ✓
+- Confirms: `stage_has_failing_test(results, "custom", "test_content_type")` will return True ✓
+
+### good-simple run (regression-good-simple-1)
+Command: `RECIPE=custom-html-tiny REF=435df8fc... SRC=recipe-maintainers/custom-html-tiny cc-ci-run runner/run_recipe_ci.py`
+Result: RC=0, install=pass, upgrade=pass, backup/restore/custom=skip
+Key output:
+- `test_serving` in install stage: PASSED ✓
+- `flags: {clean_teardown: True, no_secret_leak: True}` ✓
+- Confirms: all regression assertions for good-simple will PASS ✓
+
+### good-significant run (regression-good-significant-1) [IN PROGRESS]
+Started ~01:35Z. Multi-service stack (lasuite-docs + keycloak dep). Image pull in progress.
+Expected: GREEN (install/upgrade pass, keycloak dep provisioned, SSO tests run).