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/hermes_cli/test_skin_engine.py

@@ -196,31 +196,6 @@ class TestDisplayIntegration:
         set_active_skin("ares")
         assert get_skin_tool_prefix() == "╎"
 
-    def test_get_skin_faces_default(self):
-        from agent.display import get_skin_faces, KawaiiSpinner
-        faces = get_skin_faces("waiting_faces", KawaiiSpinner.KAWAII_WAITING)
-        # Default skin has no custom faces, so should return the default list
-        assert faces == KawaiiSpinner.KAWAII_WAITING
-
-    def test_get_skin_faces_ares(self):
-        from hermes_cli.skin_engine import set_active_skin
-        from agent.display import get_skin_faces, KawaiiSpinner
-        set_active_skin("ares")
-        faces = get_skin_faces("waiting_faces", KawaiiSpinner.KAWAII_WAITING)
-        assert "(⚔)" in faces
-
-    def test_get_skin_verbs_default(self):
-        from agent.display import get_skin_verbs, KawaiiSpinner
-        verbs = get_skin_verbs()
-        assert verbs == KawaiiSpinner.THINKING_VERBS
-
-    def test_get_skin_verbs_ares(self):
-        from hermes_cli.skin_engine import set_active_skin
-        from agent.display import get_skin_verbs
-        set_active_skin("ares")
-        verbs = get_skin_verbs()
-        assert "forging" in verbs
-
     def test_tool_message_uses_skin_prefix(self):
         from hermes_cli.skin_engine import set_active_skin
         from agent.display import get_cute_tool_message