Migrate ESLint to v9 with flat config and update dependencies

[Copilot]

• Analyze current codebase and dependencies
• Update package.json: eslint→^9, typescript-eslint@^8, globals@^16, update other major versions
  • devDependencies: @types/chai→^5, @types/mocha→^10, @types/node→^22, @types/vscode→^1.89.0, chai→^6, esbuild→^0.25, esbuild-plugin-svgr→^3, eslint→^9, added globals@^16, added typescript-eslint@^8, removed @typescript-eslint/eslint-plugin and @typescript-eslint/parser
  • dependencies: @vscode/extension-telemetry→^1.5.1
• Create eslint.config.mjs (flat config, replaces .eslintrc.json and .eslintignore)
• Delete .eslintrc.json and .eslintignore
• Update lint script (removed --ext ts flag)
• Update @vscode/extension-telemetry v0→v1 API usage in extension.ts (constructor and named import)
• Fix named import in hexDocument.ts and hexEditorProvider.ts
• Update eslint-disable comment in initWorker.ts (no-var-requires → no-require-imports)
• Run npm install
• Lint passes (eslint v9 flat config)
• TypeScript type check passes
• Code review (no actionable issues)
• CodeQL check (0 alerts)
• Merge origin/main (lodash-es bump, chore(deps-dev): bump lodash-es from 4.17.23 to 4.18.1 #595) to resolve package-lock.json conflict

[rzhao271]

@copilot Reapply changes to resolve merge conflict.

[Copilot]

@copilot Reapply changes to resolve merge conflict.

Merged origin/main (lodash-es bump from #595) into this branch and regenerated package-lock.json to resolve the conflict. Lint and type-check both pass. (9dd115b)