Add RELEASE document

Author: camdecoster

RELEASE.md

@@ -0,0 +1,105 @@
+# Releasing react-plotly.js
+
+This document covers how to cut a new release of `react-plotly.js` to npm.
+It's evergreen — substitute `X.Y.Z` with the target version (e.g. `3.0.0`)
+and `vX.Y.Z` with the git tag (e.g. `v3.0.0`).
+
+## Prerequisites
+
+- npm publish access to the [`react-plotly.js`](https://www.npmjs.com/package/react-plotly.js) package. Granted by an existing maintainer via the npm `plotly` org.
+- npm two-factor authentication configured (`npm profile get`). Publishes require an OTP.
+- Push access to `plotly/react-plotly.js` on GitHub, including tag-creation permission.
+- A clean local clone of the repo, ideally with `node_modules` reinstalled fresh against `master`.
+
+## Release sequence
+
+### 1. Pre-flight checks
+
+From the branch that will become the release and in a clean state (typically `master`, or an integration branch like `vN` that's about to merge into `master`):
+
+```bash
+npm install              # fresh install against the current lockfile
+npm test                 # lint + typecheck + jest
+npm run build            # verifies the tsup build pipeline (ESM + CJS + UMD bundles)
+npm run clean            # removes build artifacts (also runs as part of prepublishOnly)
+```
+
+`npm test` and `npm run build` must succeed. CI on the source branch should also be green.
+
+### 2. Update the changelog
+
+`CHANGELOG.md` follows [Keep a Changelog 1.1.0](https://keepachangelog.com/en/1.1.0/). For each release:
+
+1. Rename the `## [Unreleased]` heading to `## [X.Y.Z] - YYYY-MM-DD` using the actual release date.
+2. Add a fresh empty `## [Unreleased]` heading above it.
+
+Section order within a release: `Added`, `Changed`, `Deprecated`, `Removed`, `Fixed`, `Security` (omit any that have no entries). Use past-tense verbs. Link each entry to the PR that introduced it, and credit external contributors with `, with thanks to @user for the contribution!` at the end of the line.
+
+### 3. Bump the version
+
+```bash
+npm version X.Y.Z --no-git-tag-version
+```
+
+`--no-git-tag-version` prevents npm from tagging immediately; the tag is created later, after the release PR has merged.
+
+### 4. Open the release PR
+
+Branch the release off the appropriate parent — the integration branch (e.g. `vN`) for a major cumulative release, or `master` for a minor/patch. Branch name convention: `release-X.Y.Z`.
+
+```bash
+git checkout vN    # or master, depending on the release type
+git pull
+git checkout -b release-X.Y.Z
+git add *
+git commit -m "chore: release X.Y.Z"
+git push -u origin release-X.Y.Z
+gh pr create --base master --title "chore: release X.Y.Z" \
+  --body "See CHANGELOG.md entry for [$X.Y.Z]."
+```
+
+When branching from an integration branch, the PR carries all of that branch's commits plus the release-prep commits — reviewers see the full changeset alongside the version bump.
+
+### 5. Merge and tag
+
+Once the PR is reviewed, CI is green, and merged into `master`:
+
+```bash
+git checkout master
+git pull
+git tag vX.Y.Z
+git push origin vX.Y.Z
+```
+
+The tag must point at the merge commit on `master`.
+
+### 6. Publish to npm
+
+```bash
+npm publish
+```
+
+This triggers `prepublishOnly`, which runs `npm run build` (tsup, which cleans `dist/` and emits the ESM + CJS + UMD bundles + declaration files) against the current working tree before publishing. npm will prompt for the OTP from your authenticator.
+
+After publish, confirm:
+
+```bash
+npm view react-plotly.js version    # should report X.Y.Z
+npm view react-plotly.js dist-tags  # `latest` should be X.Y.Z
+```
+
+### 7. Create the GitHub release
+
+Via the GitHub UI: *Releases → Draft a new release*, target tag `vX.Y.Z`, paste the relevant `CHANGELOG.md` section into the body.
+
+## Pre-release versions
+
+For release candidates or beta builds, append a pre-release identifier and publish under a non-`latest` dist-tag so existing consumers aren't auto-upgraded:
+
+```bash
+npm version X.Y.Z-rc.0 --no-git-tag-version
+# ...PR + merge + tag as above, with tag vX.Y.Z-rc.0...
+npm publish --tag next
+```
+
+Consumers can opt in with `npm install react-plotly.js@next`.