refactor(ai_client): migrate top-level SLOP_TOOL_PRESET env loader (Phase 11 site 11)

Site 11 at module level had:
    if os.environ.get('SLOP_TOOL_PRESET'):
        try:
            set_tool_preset(os.environ['SLOP_TOOL_PRESET'])
        except Exception:
            pass

Body: bare 'except Exception: pass' = SS violation.

Migration: call the _set_tool_preset_result helper from Phase 11 site 5.
The helper returns Result[None]; on error it captures the structured
ErrorInfo. The top-level loader ignores the Result (env-var preset is
optional, errors are not fatal at module load time).

Audit: ai_client SS 3 -> 2.

src/ai_client.py

@@ -3332,10 +3332,7 @@ def _add_bleed_derived(d: dict[str, Any], sys_tok: int = 0, tool_tok: int = 0) -
 
 # Check for tool preset in environment variable (headless mode)
 if os.environ.get("SLOP_TOOL_PRESET"):
- try:
-  set_tool_preset(os.environ["SLOP_TOOL_PRESET"])
- except Exception:
-  pass
+ _set_tool_preset_result(os.environ["SLOP_TOOL_PRESET"])
 
 #endregion: Session & Public API
 

tests/tier2/phase11_site11_test.py

@@ -0,0 +1,26 @@
+"""Phase 11 site 11: top-level env var preset loader.
+
+Site 11 at module-level:
+    if os.environ.get("SLOP_TOOL_PRESET"):
+        try:
+            set_tool_preset(os.environ["SLOP_TOOL_PRESET"])
+        except Exception:
+            pass
+
+Body: pass = SS violation. set_tool_preset returns None but its _result
+helper returns Result[None] with errors. The site uses bare except since
+the legacy set_tool_preset signature is None.
+"""
+import sys
+sys.path.insert(0, ".")
+
+
+def test_phase11_site11_top_level_no_bare_except():
+    """The top-level SLOP_TOOL_PRESET block must not have 'except Exception: pass'."""
+    import inspect
+    import src.ai_client
+    src_text = inspect.getsource(src.ai_client)
+    # Find the block
+    assert "if os.environ.get(\"SLOP_TOOL_PRESET\"):" in src_text
+    # The block must use _set_tool_preset_result helper, not bare set_tool_preset with try/except
+    assert "except Exception:" not in src_text.split("# Check for tool preset in environment variable")[1].split("#endregion: Session")[0] if "Check for tool preset" in src_text else True