fix: remove 115 verified dead code symbols across 46 production files

Automated dead code audit using vulture + coverage.py + ast-grep intersection,
confirmed by Opus deep verification pass. Every symbol verified to have zero
production callers (test imports excluded from reachability analysis).

Removes ~1,534 lines of dead production code across 46 files and ~1,382 lines
of stale test code. 3 entire files deleted (agent/builtin_memory_provider.py,
hermes_cli/checklist.py, tests/hermes_cli/test_setup_model_selection.py).

Co-authored-by: alt-glitch <balyan.sid@gmail.com>

tests/gateway/test_delivery.py

@@ -1,7 +1,7 @@
 """Tests for the delivery routing module."""
 
 from gateway.config import Platform, GatewayConfig, PlatformConfig, HomeChannel
-from gateway.delivery import DeliveryRouter, DeliveryTarget, parse_deliver_spec
+from gateway.delivery import DeliveryRouter, DeliveryTarget
 from gateway.session import SessionSource
 
 
@@ -41,28 +41,6 @@ class TestParseTargetPlatformChat:
         assert target.platform == Platform.LOCAL
 
 
-class TestParseDeliverSpec:
-    def test_none_returns_default(self):
-        result = parse_deliver_spec(None)
-        assert result == "origin"
-
-    def test_empty_string_returns_default(self):
-        result = parse_deliver_spec("")
-        assert result == "origin"
-
-    def test_custom_default(self):
-        result = parse_deliver_spec(None, default="local")
-        assert result == "local"
-
-    def test_passthrough_string(self):
-        result = parse_deliver_spec("telegram")
-        assert result == "telegram"
-
-    def test_passthrough_list(self):
-        result = parse_deliver_spec(["local", "telegram"])
-        assert result == ["local", "telegram"]
-
-
 class TestTargetToStringRoundtrip:
     def test_origin_roundtrip(self):
         origin = SessionSource(platform=Platform.TELEGRAM, chat_id="111", thread_id="42")