Add support for loading TypeScript functions using tsx in the Functions Emulator

[taeold]

Emulator will try to detect use of TypeScript by checking existence of tsconfig.json and will prefer using tsx in place of node to start the process for loading and executing functions.

This allows developers to skip running TS compilation on the side - index.ts file will be read directly by the Functions Emulator!

[Copilot]

Pull Request Overview

This PR adds support for loading TypeScript functions using tsx in the Functions Emulator so that developers can run TypeScript files directly without a separate compile step.

• Added tsx as a dependency in package files.
• Updated the functions emulator runtime and delegate logic to override the entry point for TypeScript projects.
• Introduced getTypeScriptEntryPoint to resolve the TypeScript source file and added an isEmulator flag to control TS-specific behavior.

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
templates/init/functions/typescript/package.nolint.json	Added the "tsx" dependency alongside firebase-functions-test.
templates/init/functions/typescript/package.lint.json	Added the "tsx" dependency alongside typescript.
src/emulator/functionsEmulatorRuntime.ts	Modified trigger loading to check for a custom entry point for TS files.
src/emulator/functionsEmulator.ts	Introduced the isEmulator flag and set FUNCTIONS_SOURCE in the env vars.
src/deploy/functions/runtimes/node/index.ts	Added getTypeScriptEntryPoint and updated Delegate to support TS projects.
src/deploy/functions/runtimes/index.ts	Extended DelegateContext with isEmulator flag.
CHANGELOG.md	Documented support for loading TypeScript functions with tsx.