fix(coding-agent): remove process-cwd tool singletons and use tool-name allowlists

- switch SDK/CLI tool selection to name-based allowlists
- apply allowlists across built-in, extension, and SDK tools
- remove ambient process.cwd defaults from core tooling and resource helpers
- update tests, examples, and TUI callers for explicit cwd plumbing
- add regression coverage for extension tool filtering

closes #3452
closes #2835

packages/coding-agent/src/core/tools/edit.ts

@@ -485,7 +485,3 @@ export function createEditToolDefinition(
 export function createEditTool(cwd: string, options?: EditToolOptions): AgentTool<typeof editSchema> {
 	return wrapToolDefinition(createEditToolDefinition(cwd, options));
 }
-
-/** Default edit tool using process.cwd() for backwards compatibility. */
-export const editToolDefinition = createEditToolDefinition(process.cwd());
-export const editTool = createEditTool(process.cwd());