Remove TypeScript path mappings in favor of relative imports

Fixes https://github.com/xtermjs/xterm.js/issues/5896

TypeScript path mappings for common/*, browser/*, and headless/*
were not rewritten in emitted JavaScript, which forced webpack resolve
aliases and NODE_PATH workarounds so runtime could resolve modules.
That added build complexity and broke tooling such as ESLint import/no-cycle.

Changes:
- Convert ~750 imports across src/, addons/, and test/ to relative paths
- Remove common/browser/headless paths and src catch-all mappings from tsconfigs
  (keep @xterm/addon-* demo and addon typings paths)
- Remove webpack resolve.alias for common, browser, headless, and vs
- Drop NODE_PATH from unit tests, benchmarks, and VS Code launch config
- Fix addon-image IIPImageStorage to import ./Types after removing catch-all *

Verified: npm run build, esbuild, package, package-headless
Co-authored-by: Cursor <cursoragent@cursor.com>

addons/addon-unicode11/src/UnicodeV11.ts

@@ -4,8 +4,8 @@
  */
 
 import { IUnicodeVersionProvider } from '@xterm/xterm';
-import { UnicodeCharProperties, UnicodeCharWidth } from 'common/services/Services';
-import { UnicodeService } from 'common/services/UnicodeService';
+import { UnicodeCharProperties, UnicodeCharWidth } from '../../../src/common/services/Services';
+import { UnicodeService } from '../../../src/common/services/UnicodeService';
 
 const BMP_COMBINING = [
   [0x0300, 0x036F], [0x0483, 0x0489], [0x0591, 0x05BD],

addons/addon-unicode11/src/tsconfig.json

@@ -12,14 +12,8 @@
     "removeComments": true,
     "strict": true,
     "paths": {
-      "common/*": [
-        "../../../src/common/*"
-      ],
       "@xterm/addon-unicode11": [
         "../typings/addon-unicode11.d.ts"
-      ],
-      "*": [
-        "./*"
       ]
     },
     "types": [