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-serialize/src/SerializeAddon.test.ts

@@ -6,10 +6,10 @@
 import jsdom = require('jsdom');
 import { assert } from 'chai';
 import { SerializeAddon } from './SerializeAddon';
-import { Terminal } from 'browser/public/Terminal';
-import { SelectionModel } from 'browser/selection/SelectionModel';
-import { IBufferService } from 'common/services/Services';
-import { ThemeService } from 'browser/services/ThemeService';
+import { Terminal } from '../../../src/browser/public/Terminal';
+import { SelectionModel } from '../../../src/browser/selection/SelectionModel';
+import { IBufferService } from '../../../src/common/services/Services';
+import { ThemeService } from '../../../src/browser/services/ThemeService';
 
 function sgr(...seq: string[]): string {
   return `\x1b[${seq.join(';')}m`;

addons/addon-serialize/src/SerializeAddon.ts

@@ -7,9 +7,9 @@
 
 import type { IBuffer, IBufferCell, IBufferRange, ITerminalAddon, Terminal } from '@xterm/xterm';
 import type { IHTMLSerializeOptions, SerializeAddon as ISerializeApi, ISerializeOptions, ISerializeRange } from '@xterm/addon-serialize';
-import { IAttributeData, IColor } from 'common/Types';
-import { DEFAULT_ANSI_COLORS } from 'browser/Types';
-import { UnderlineStyle } from 'common/buffer/Constants';
+import { IAttributeData, IColor } from '../../../src/common/Types';
+import { DEFAULT_ANSI_COLORS } from '../../../src/browser/Types';
+import { UnderlineStyle } from '../../../src/common/buffer/Constants';
 
 function constrain(value: number, low: number, high: number): number {
   return Math.max(low, Math.min(value, high));

addons/addon-serialize/src/tsconfig.json

@@ -11,12 +11,6 @@
     "sourceMap": true,
     "removeComments": true,
     "paths": {
-      "common/*": [
-        "../../../src/common/*"
-      ],
-      "browser/*": [
-        "../../../src/browser/*"
-      ],
       "@xterm/addon-serialize": [
         "../typings/addon-serialize.d.ts"
       ]