refactor: rename files to PascalCase components and kebab-case APIs (Task 4.4)

- Rename all component files to PascalCase matching exported names
- Move components into feature directories (git/, session/, project/, terminal/, workspace/, ui/, layout/)
- Rename all page files to PascalCase with Page suffix
- Rename all API files to kebab-case
- Update all imports across codebase with corrected relative depths
- Preserve git history via git mv

Quality gates: tsc (pass), eslint (pass), 66/74 tests pass (8 pre-existing failures)
Refs: repo-restructure Task 4.4

apps/web/src/components/features/session/CreateSessionForm.test.tsx

@@ -17,7 +17,7 @@ vi.mock("@/api/settings", () => ({
 	updateUserConfig: vi.fn(),
 }));
 
-import { listRepositories } from "@/api/git_repositories";
+import { listRepositories } from "@/api/git-repositories";
 import { createInstance } from "@/api/sessions";
 
 const mockProjects = [