website: add cn1playground version updates and source-based CN1 access registry generation

[shai-almog]

Motivation

• Add Playground to the website automation so Codename One versions for the playground are kept in sync with releases.
• Make the Playground build use the same managed cn1.version handling as other site artifacts and allow opting into bootstrapped local CN1 snapshots.
• Generate the BeanShell CN1 access registry from CN1 source trees (or explicit source roots) to support builds from Maven source jars or a local workspace.

Description

• Rename the workflow to Website CN1 Version PR and update the job name, commit message, PR title, labels, and paths to include scripts/cn1playground in /.github/workflows/initializr-cn1-version-pr.yml.
• Add scripts/cn1playground/update-cn1-version.sh which determines a CN1 plugin version from an optional tag or Maven Central metadata and updates scripts/cn1playground/pom.xml.
• Change scripts/cn1playground/pom.xml to set <cn1.plugin.version>${cn1.version}</cn1.plugin.version>, provide a default <cn1.version>7.0.230</cn1.version>, and add a cn1-local-workspace profile that activates 8.0-SNAPSHOT when -Dcn1.localWorkspace=true.
• Extend scripts/cn1playground/tools/generate-cn1-access-registry.sh to resolve and unpack CN1 source jars for the configured cn1.version and invoke the generator with CN1_SOURCE_ROOTS.
• Modify GenerateCN1AccessRegistry.java to accept configured CN1 source roots from the CN1_SOURCE_ROOTS environment variable and fall back to locating a local CN1 root if none are provided.
• Update scripts/cn1playground/tools/README.md to document the new source-jar based registry generation behavior.
• Update scripts/website/build.sh to detect WEBSITE_CN1_VERSION from scripts/cn1playground/pom.xml, call scripts/cn1playground/update-cn1-version.sh when building the playground, and pass the cn1.localWorkspace flag into the playground Maven invocation when bootstrapping snapshots.

Testing

• No automated tests were executed as part of this change set.

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Codex Task

[github-actions]

Cloudflare Preview

• URL: https://pr-4658-website-preview.codenameone.pages.dev
• Branch: pr-4658-website-preview