refactor(tools): consolidate LLM tools from 42 to 38

Merge create_task into create_note (set status='todo' for tasks, omit
for notes), merge delete_task into delete_note, consolidate entity
tools (create/update_person → save_person, create/update_place →
save_place), rename get_note → read_note with clearer descriptions,
move calculate out of rag.py into utility.py, and extract shared
duplicate detection into check_duplicate() helper.

Updates all downstream references in generation_task.py, quick_capture.py,
ToolCallCard.vue, and WorkspaceView.vue.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/fabledassistant/services/tools/rag.py

@@ -1,4 +1,4 @@
-"""RAG scope and calculation tools."""
+"""RAG scope tool."""
 
 from __future__ import annotations
 
@@ -32,32 +32,3 @@ async def set_rag_scope_tool(*, user_id, arguments, conv_id=None, workspace_proj
     from fabledassistant.services.chat import update_conversation
     await update_conversation(user_id, conv_id, rag_project_id=project_id)
     return {"success": True, "type": "rag_scope_set", "scope_label": scope_label}
-
-
-@tool(
-    name="calculate",
-    description=(
-        "Evaluate a mathematical expression and return the exact result. Use this for any "
-        "arithmetic, percentages, unit conversions, or multi-step calculations where precision "
-        "matters. Supports standard math operators (+, -, *, /, **, %) and all Python math "
-        "module functions (sqrt, log, sin, cos, floor, ceil, etc.)."
-    ),
-    parameters={
-        "expression": {"type": "string", "description": "A valid Python math expression (e.g. '(450 * 1.13) / 12', 'sqrt(144)', 'log(1000, 10)')"},
-    },
-    required=["expression"],
-)
-async def calculate_tool(*, user_id, arguments, **_ctx):
-    import math as _math
-
-    expr = str(arguments.get("expression", "")).strip()
-    if not expr:
-        return {"success": False, "error": "expression is required"}
-    allowed_names = {k: v for k, v in vars(_math).items() if not k.startswith("_")}
-    allowed_names["abs"] = abs
-    allowed_names["round"] = round
-    try:
-        result = eval(expr, {"__builtins__": {}}, allowed_names)  # noqa: S307
-    except Exception as calc_err:
-        return {"success": False, "error": f"Could not evaluate expression: {calc_err}"}
-    return {"success": True, "type": "calculation", "data": {"expression": expr, "result": result}}