[AZ-494] [AZ-492] Cycle 3 Step 16: full test suite green; close batches

Final cumulative review for batches 04-05 (PASS_WITH_WARNINGS, 4 Low
findings, all non-blocking). Combined with the prior 01-03 cumulative,
this closes the per-cycle batch coverage with two PASS_WITH_WARNINGS
verdicts.

scripts/run-tests.sh --full green: format check + 13 cycle-3 unit
tests (including the 4 new AZ-494 fail-fast cases for missing /
empty iss / aud) + the full integration suite (including the 2 new
WrongIssuer / WrongAudience 401 assertions).

Fixed a stale "leave blank to fall back" comment in .env.example
that contradicted the "REQUIRED" line right above it; the integration
runner reads env vars directly with no appsettings fallback so blank
values now fail-fast.

Advanced _docs/_autodev_state.md to mark Step 10 (Implement) status:
completed.

Co-authored-by: Cursor <cursoragent@cursor.com>

_docs/_autodev_state.md

@@ -4,11 +4,11 @@
 flow: existing-code
 step: 10
 name: Implement
-status: not_started
+status: completed
 sub_step:
-  phase: 0
-  name: awaiting-invocation
-  detail: ""
+  phase: 16
+  name: full-test-suite-passed
+  detail: "Step 16 PASS: ./scripts/run-tests.sh --full green. 5 batches landed (AZ-495+AZ-496, AZ-491, AZ-493, AZ-492, AZ-494). 2 cumulative reviews: 01-03 + 04-05 both PASS_WITH_WARNINGS. AZ-494 AC-1/2 wrong-iss/wrong-aud assertions both PASS in integration log line 650/653. 4 new fail-fast unit tests PASS. Cycle 3 implementation complete."
 retry_count: 0
 cycle: 3
 tracker: jira