docs: update documentation to use pnpm over yarn

[daniel-graham-amplitude]

Summary

(see title)

Checklist

• Does your PR title have the correct title format?
• Does your PR have a breaking change?: No

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Note

Standardizes tooling to pnpm

• Replace yarn with pnpm across README.md, CONTRIBUTING.md, AGENTS.md, test-server/README.md, and test-server/proxy-test.html
• Update Bug_report.md environment section to include pnpm and correct casing
• Switch package scripts to pnpm in package.json for plugin-autocapture-browser (watch-bundle) and align version-file scripts in plugin-session-replay-browser, segment-session-replay-plugin, session-replay-browser, and unified

No runtime code changes

^{Written by Cursor Bugbot for commit 32b6f23. This will update automatically on new commits. Configure here.}

[macroscopeapp]

Replace Yarn with PNPM across docs and scripts to migrate amplitude-typescript per AMP-145286

Update documentation and package scripts to use pnpm commands; remove PNPM setup step from publish-single-package.yml.

🖇️ Linked Issues

This PR implements the migration in AMP-145286 under the AMP-145285 epic and contributes to the AMP-91393 initiative by standardizing pnpm usage.

📍Where to Start

Start with the workflow change in publish-single-package.yml to verify CI behavior, then review documentation updates in README.md.

Changes since #1449 opened

• Added pnpm/action-setup@v4 setup step to the publish-single-package GitHub Actions workflow [32b6f23]

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Macroscope summarized 8b992d0.

[Copilot]

Pull request overview

This PR updates all documentation references from yarn to pnpm to reflect the project's migration to pnpm as the package manager.

• Updates command examples in documentation files (README, CONTRIBUTING, AGENTS)
• Updates inline comments in package.json scripts to reflect pnpm usage
• Updates HTML test page instructions
• Updates issue template to mention pnpm as an installation method

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
test-server/proxy-test.html	Updates proxy server command from yarn to pnpm
test-server/README.md	Updates all development and production commands from yarn to pnpm
packages/unified/package.json	Updates autogenerated script comment from yarn to pnpm
packages/session-replay-browser/package.json	Updates autogenerated script comment from yarn to pnpm
packages/segment-session-replay-plugin/package.json	Updates autogenerated script comment from yarn to pnpm
packages/plugin-session-replay-browser/package.json	Updates autogenerated script comment from yarn to pnpm
packages/plugin-autocapture-browser/package.json	Updates watch-bundle script to use pnpm
README.md	Updates getting started and troubleshooting commands from yarn to pnpm
CONTRIBUTING.md	Updates build/test commands and build system reference from yarn to pnpm
AGENTS.md	Updates all testing and linting commands from yarn to pnpm
.github/ISSUE_TEMPLATE/Bug_report.md	Adds pnpm to installation methods list

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[Copilot]

The capitalization is inconsistent here. The comment uses lowercase "yarn" but uppercase "NPM". For consistency, consider either capitalizing all package managers (NPM/Yarn/pnpm) or using all lowercase (npm/yarn/pnpm). The common convention is to use lowercase for package manager names when referring to the CLI tools.

Suggested change

	- Installation Method: <!-- I.e. NPM/yarn/pnpm or <script> import -->
	- Installation Method: <!-- I.e. npm/yarn/pnpm or <script> import -->

[Mercy811]

LGTM!

[cursor]

Removed pnpm setup action breaks CI workflow

The pnpm/action-setup@v4 action step was removed, but the workflow still uses pnpm commands (pnpm install, pnpm build, pnpm test, etc.). While actions/setup-node@v4 with cache: "pnpm" handles caching, it does not install pnpm itself. All other workflow files in this repository (ci.yml, ci-nx.yml, docs.yml, e2e.yml) correctly include the pnpm setup step before setup-node. Without this action, the pnpm binary won't be available and the workflow will fail.