refactor: unify AI capabilities and workspace integration

backend/tests/test_research_integration.py

@@ -6,7 +6,8 @@ import pytest
 from fastapi import HTTPException
 from sqlalchemy import func, select
 
-from app.ai.tools import CATALOG, read_tool
+from app.ai.capabilities import ToolContext
+from app.ai.tools import CAPABILITIES
 from app.alphas import upsert_alpha
 from app.backtests.contracts import PreviewInput, RerunInput, SubsetInput
 from app.business import Business
@@ -137,7 +138,7 @@ async def test_invalid_construction_has_no_partial_preview(logged_in, app, fixed
 async def test_input_pagination_old_types_and_explicit_exclusions(app, logged_in, catalog, fixed_input):
     async def tool(name, args):
         async with app.state.sessions.begin() as db:
-            return await read_tool(Business(db), name, CATALOG[name][0].model_validate(args))
+            return await CAPABILITIES[name].invoke(ToolContext(Business(db)), args)
 
     page = await tool("get_research_input", {"input_id": fixed_input["id"], "offset": 100, "limit": 25})
     assert page["field_count"] == page["total"] == 123 and len(page["items"]) == 23