feat(ts): ts/unused-import rule — whole-statement delete of dead TS/JS imports

- binds names via tree-sitter (default, namespace, named + alias, type-only),
  keeps a statement when ANY bound name occurs outside it (word scan over
  comments/strings included): under-delete is the safe direction, mirroring
  the Java rule's asymmetry
- ESM caveat encoded in the policy: mixed live/dead statements are not
  touched — removing a specifier would still drop the module's side effects
- side-effect imports and 'export .. from' re-exports are never candidates
- parser/ts became a folder (mod/extract/unused_imports) to keep the
  4-entries-per-module rule; word_occurs shared via crate::parser
- java/rules/unused_imports now reuses the shared word scanner (DRY)

tests/typescript/unused/package.json

@@ -0,0 +1 @@
+{ "name": "unused-fixture" }

tests/typescript/unused/src/app.ts

@@ -0,0 +1,10 @@
+import { used, unused } from './lib';
+import './side-effects';
+import Logger from './logger'; // used below, keep it
+import type { Ghost } from './types';
+
+export function run(): number {
+  const log = new Logger();
+  log.write('hello');
+  return used(1, 2);
+}

tests/typescript/unused/src/lib.ts

@@ -0,0 +1,6 @@
+export function used(a: number, b: number): number {
+  return a + b;
+}
+export function unused(a: number): number {
+  return a;
+}

tests/typescript/unused/src/logger.ts

@@ -0,0 +1,3 @@
+export default class Logger {
+  write(_s: string) {}
+}