fix(tests): purge theater/broken tests, fix Config argparse pollution, fix is_ad() false positive

PHASE 1 — STOP THE BLEEDING:
- Delete 6 theater/dead test files (empty stubs, skipped placeholders)
- Create root conftest.py to isolate Config/argparse from pytest sys.argv
- Rewrite test_feed_loop_continuation.py: replace inspect.getsource() theater
  with real DopamineEngine behavior tests
- Rewrite test_ad_detection.py: use existing XML fixtures instead of phantoms
- Rewrite test_false_positive.py: use verified fixtures, caught REAL bug

PRODUCTION FIX:
- Fix is_ad() false positive: regex \bad\b was matching 'Create messaging ad'
  in DM inbox. Changed to exact label matching (text/desc must BE the ad marker,
  not merely contain it)

Result: 34 FAILED + 4 ERRORS -> 0 FAILED, 178 PASSED, 3 SKIPPED

tests/e2e/test_e2e_animation_timing.py

@@ -1,6 +0,0 @@
-import pytest
-
-
-@pytest.mark.skip(reason="Lying mock tests removed: BehaviorSimulator and str.replace theater have been purged.")
-def test_animation_timing_mocks_purged():
-    pass

tests/e2e/test_sim_full_lifecycle.py

@@ -1,8 +0,0 @@
-import pytest
-
-
-@pytest.mark.skip(
-    reason="Lying mock tests removed: Full lifecycle sim patched TelepathicEngine and used string transitions."
-)
-def test_full_lifecycle_sim_purged():
-    pass