Export arbitrary WordPress sites as replayable Playground blueprint bundles

[chubes4]

Problem

Workflow Bench needs every website-generation adapter to leave behind a durable, replayable WordPress site, not just logs or copied files. Some generated sites come from WP Codebox runtimes, but others come from external/local WordPress sites such as Studio-managed sites. Those external generated sites need a generic export path into a replayable Playground/WP Codebox bundle.

Existing issue #220 covered replayable runtime snapshot bundles for WP Codebox-owned runtimes. This issue extends the requirement to arbitrary generated WordPress sites that were not originally created inside a Codebox runtime.

Desired capability

Provide a generic exporter that can take a generated WordPress site source and produce a durable replay bundle.

Inputs could include:

• a WordPress site path on disk
• a WP Codebox runtime
• a Studio-generated local site directory
• a generated artifact bundle with WordPress files/state

Output should be a replayable bundle, for example:

• manifest.json
• blueprint.json
• files/ containing themes/plugins/uploads/import payloads as needed
• site-state export where needed for pages/options/terms/templates/media
• replay limitations/diagnostics
• SHA-256 verified artifact refs

Acceptance criteria

• A generated WordPress site outside Codebox can be exported into a wp-codebox/replayable-wordpress-site/v1 style bundle.
• The bundle can be replayed in WP Playground / WP Codebox without relying on the original local site path.
• The bundle preserves enough state to inspect generated pages, templates, active theme/plugins, media/uploads, and relevant options.
• The manifest clearly distinguishes fully replayable state from partial/limited captures.
• The command is policy-controlled and does not implicitly export private sites.
• Workflow Bench can consume the emitted bundle as a durable generated-site artifact.

Non-goals

• Do not score generation quality here.
• Do not add Studio-specific behavior to WP Codebox; Studio should be just one consumer/source.
• Do not require changes in Automattic/studio for the initial capability.