fix: complete refactoring integration — rename remaining snake_case API files and fix test imports

During refactoring verification found several remaining inconsistencies:

API files (kebab-case naming):
- Rename config_profiles.ts → config-profiles.ts
- Rename tool_definitions.ts → tool-definitions.ts
- Update all imports across 8 files

Missing Python __init__.py (backend package structure):
- Add utils/__init__.py
- Add services/__init__.py
- Add schemas/__init__.py
- Add services/build/__init__.py

Test file import fixes (component reorganization fallout):
- DashboardPage.test.tsx: import from ./dashboard → ./DashboardPage
- ProjectsPage.test.tsx: import from ./projects → ./ProjectsPage
- event-toast-bridge.test.tsx: fix relative paths for moved components
  (../state/events → ../../../state/events, ./toast-rules → ../../toast-rules)
- notification-center.test.tsx: fix relative path
  (../state/notifications → ../../../state/notifications)

Quality gates: tsc --noEmit (pass), build (pass), py_compile (pass)
Tests: 9/12 test files pass (3 pre-existing UI test failures unrelated to refactoring)

apps/web/src/pages/ProjectsPage.test.tsx

@@ -2,7 +2,7 @@ import { cleanup, fireEvent, render, screen, waitFor, within } from "@testing-li
 import { MemoryRouter } from "react-router-dom";
 import { afterEach, describe, expect, it, vi } from "vitest";
 
-import { ProjectsPage } from "./projects";
+import { ProjectsPage } from "./ProjectsPage";
 import * as projectsApi from "../api/projects";
 
 const mockProjects = [