Repository: JoshuaKGoldberg/create-typescript-app (ts)

Issue:
🐛 Bug: Crash in --mode create if pnpm version mismatches 
### Bug Report Checklist

- [X] I have tried restarting my IDE and the issue persists.
- [X] I have pulled the latest `main` branch of the repository.
- [X] I have [searched for related issues](https://github.com/JoshuaKGoldberg/create-typescript-app/issues?q=is%3Aissue) and found none that matched my issue.

### Expected

When you run `npx create-typescript-app --mode create ...`, the CLI should create a new repository as long as you have Node.js and pnpm installed.

### Actual

If your local pnpm version isn't the expected one:

```plaintext
◇  ❌ Error installing packages.
│
Error: Failed installing packages
    at withSpinner (file:///Users/josh/.npm/_npx/a296d102f6ed205b/node_modules/create-typescript-app/lib/shared/cli/spinners.js:16:11)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async createWithOptions (file:///Users/josh/.npm/_npx/a296d102f6ed205b/node_modules/create-typescript-app/lib/create/createWithOptions.js:33:5)
    ... 3 lines matching cause stack trace ...
    at async bin (file:///Users/josh/.npm/_npx/a296d102f6ed205b/node_modules/create-typescript-app/lib/bin/index.js:67:36)
    at async file:///Users/josh/.npm/_npx/a296d102f6ed205b/node_modules/create-typescript-app/bin/index.js:4:20 {
  [cause]: Error: Command failed with exit code 1: pnpm add @release-it/conventional-changelog@latest @types/eslint@latest @typescript-eslint/eslint-plugin@latest @typescript-eslint/parser@latest @vitest/coverage-v8@latest all-contributors-cli@latest console-fail-test@latest cspell@latest eslint@latest eslint-plugin-deprecation@latest eslint-plugin-eslint-comments@latest eslint-plugin-jsdoc@latest eslint-plugin-jsonc@latest eslint-plugin-markdown@latest eslint-plugin-n@latest eslint-plugin-package-json@latest eslint-plugin-perfectionist@latest eslint-plugin-regexp@latest eslint-plugin-vitest@latest eslint-plugin-yml@latest husky@latest jsonc-eslint-parser@latest knip@latest lint-staged@latest markdownlint@latest markdownlint-cli@latest prettier@latest prettier-plugin-curly@latest prettier-plugin-packagejson@latest release-it@latest sentences-per-line@latest tsup@latest typescript@latest vitest@latest yaml-eslint-parser@latest -D
   ERR_PNPM_BAD_PM_VERSION  This project is configured to use v8.15.4 of pnpm. Your current pnpm is v9.0.6

  If you want to bypass this version check, you can set the "package-manager-strict" configuration to "false" or set the "COREPACK_ENABLE_STRICT" environment variable to "0"
```

### Additional Info

I'm not sure what the right resolution would be... changing the pnpm version to the user's? Prompting them to install a new one? Disabling strict pnpm version checks? ...?

Pull request description:
fix: remove package.json packageManager field
## PR Checklist

- [x] Addresses an existing open issue: fixes #1513
- [x] That issue was marked as [`status: accepting prs`](https://github.com/JoshuaKGoldberg/create-typescript-app/issues?q=is%3Aopen+is%3Aissue+label%3A%22status%3A+accepting+prs%22)
- [x] Steps in [CONTRIBUTING.md](https://github.com/JoshuaKGoldberg/create-typescript-app/blob/main/.github/CONTRIBUTING.md) were taken

## Overview

Right now, trying to use `create-typescript-app` with anything but the _exact correct pnpm major.minor.patch version_ installed produces an error. That's very annoying.

Pending https://github.com/nodejs/corepack/issues/95, removes usage of the [experimental `package.json` `packageManager` field](https://nodejs.org/api/packages.html#packagemanager).

Patch:
diff --git a/.github/actions/prepare/action.yml b/.github/actions/prepare/action.yml
index cb825e6..1c10c25 100644
--- a/.github/actions/prepare/action.yml
+++ b/.github/actions/prepare/action.yml
@@ -5,6 +5,8 @@ name: Prepare
 runs:
   steps:
     - uses: pnpm/action-setup@v2
+      with:
+        version: 9
     - uses: actions/setup-node@v4
       with:
         cache: pnpm
diff --git a/package.json b/package.json
index 87fd9f1..6326167 100644
--- a/package.json
+++ b/package.json
@@ -100,7 +100,6 @@
 		"typescript-eslint": "^7.7.0",
 		"vitest": "^1.4.0"
 	},
-	"packageManager": "pnpm@9.1.0",
 	"engines": {
 		"node": ">=18"
 	},
diff --git a/src/steps/writing/creation/dotGitHub/actions.ts b/src/steps/writing/creation/dotGitHub/actions.ts
index 3ed304d..f04ba91 100644
--- a/src/steps/writing/creation/dotGitHub/actions.ts
+++ b/src/steps/writing/creation/dotGitHub/actions.ts
@@ -9,7 +9,10 @@ export function createDotGitHubActions() {
 					name: "Prepare",
 					runs: {
 						steps: [
-							{ uses: "pnpm/action-setup@v2" },
+							{
+								uses: "pnpm/action-setup@v2",
+								with: { version: 9 },
+							},
 							{
 								uses: "actions/setup-node@v4",
 								with: { cache: "pnpm", "node-version": "20" },
diff --git a/src/steps/writing/creation/writePackageJson.ts b/src/steps/writing/creation/writePackageJson.ts
index 4862638..a04b770 100644
--- a/src/steps/writing/creation/writePackageJson.ts
+++ b/src/steps/writing/creation/writePackageJson.ts
@@ -75,7 +75,6 @@ export async function writePackageJson(options: Options) {
 		},
 		main: "./lib/index.js",
 		name: options.repository,
-		packageManager: "pnpm@9.1.0",
 		publishConfig: {
 			provenance: true,
 		},


Test patch:
diff --git a/src/steps/writing/creation/dotGitHub/actions.test.ts b/src/steps/writing/creation/dotGitHub/actions.test.ts
index 7990bb3..66cceed 100644
--- a/src/steps/writing/creation/dotGitHub/actions.test.ts
+++ b/src/steps/writing/creation/dotGitHub/actions.test.ts
@@ -15,6 +15,8 @@ name: Prepare
 runs:
   steps:
     - uses: pnpm/action-setup@v2
+      with:
+        version: 9
     - uses: actions/setup-node@v4
       with:
         cache: pnpm
diff --git a/src/steps/writing/creation/writePackageJson.test.ts b/src/steps/writing/creation/writePackageJson.test.ts
index 20d480c..9bb9219 100644
--- a/src/steps/writing/creation/writePackageJson.test.ts
+++ b/src/steps/writing/creation/writePackageJson.test.ts
@@ -91,7 +91,6 @@ describe("writePackageJson", () => {
 			  },
 			  "main": "./lib/index.js",
 			  "name": "test-repository",
-			  "packageManager": "pnpm@9.1.0",
 			  "publishConfig": {
 			    "provenance": true,
 			  },
@@ -162,7 +161,6 @@ describe("writePackageJson", () => {
 			  },
 			  "main": "./lib/index.js",
 			  "name": "test-repository",
-			  "packageManager": "pnpm@9.1.0",
 			  "publishConfig": {
 			    "provenance": true,
 			  },