feat: migrate npm package to @flagsmith organization scope

[kyle-ssg]

Summary

• Renames flagsmith-cli → @flagsmith/cli (major version bump 0.2.3 → 1.0.0)
• Bumps bundled JS client dep flagsmith@^9.0.5 → @flagsmith/flagsmith@^12.0.0
• Adds publishConfig: { access: "public" } so first scoped publish is public
• Updates README install snippets and example imports

Related PRs

• feat: migrate npm package to @flagsmith organization scope flagsmith-nodejs-client#270 — same migration for flagsmith-nodejs → @flagsmith/nodejs
• docs: migrate flagsmith-cli and flagsmith-nodejs references to @flagsmith scope flagsmith#7583 — updates the in-app code-help and docs snippets to reference the new scoped names

Publish sequence

The PR ships with version: "1.0.0" because that is the canonical first stable release of the scoped package. To work around the trusted-publisher chicken-and-egg, the first push to npm happens locally as a prerelease (mirroring flagsmith-js-client which ran 11.0.0-internal.0 … .7 before 11.0.0):

1. Locally from this branch, logged into npm with @flagsmith org write access:

   npm install && npm run build
   npm version 1.0.0-internal.0 --no-git-tag-version   # edits package.json only, not committed
   npm publish --tag internal
   git checkout package.json package-lock.json         # discard the local version edit

   The package is now on npm under the internal dist-tag. latest is still empty so npm i @flagsmith/cli does not pick up the prerelease.
2. On npmjs.com, configure the trusted publisher entry for @flagsmith/cli pointing at this repo + .github/workflows/publish.yml.
3. Iterate (bump to internal.1, .2, …) the same way until happy.
4. Cut the real 1.0.0 either by another local npm publish from the merged commit, or by merging this PR and letting release-please / CI publish via OIDC.
5. npm deprecate flagsmith-cli@"*" "Moved to @flagsmith/cli" to redirect existing users.

Test plan

• npm install resolves cleanly on the new dep
• npm run build succeeds
• flagsmith get CLI command still produces a valid flagsmith.json against a real environment
• First manual publish lands @flagsmith/cli@1.0.0-internal.0 on the internal dist-tag

🤖 Generated with Claude Code